Ferroelectric liquid crystal display with a reduced light-transmittance dependency upon a visible angle

ABSTRACT

A ferroelectric liquid crystal display includes a pair of first and second substrates placed substantially in parallel to each other to form a space between the first and second substrates so that a ferroelectric liquid crystal is provided in the space between the first and second substrates, wherein the ferroelectric liquid crystal is isolated into co-existent separate orientation regions that have crystal orientations which differ by 90 degrees from each other in initial orientation direction of an optical axis of ferroelectric liquid crystal molecules when no electric field is applied to the ferroelectric liquid crystal immediately after the ferroelectric liquid crystal has been injected into the space between the first and second substrates.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a liquid crystal display, andmore particularly to a liquid crystal display using ferroelectric orantiferroelectric liquid crystal with an improved visible angledependency.

[0002] The liquid crystal display has widely been used in various fieldsfor watches, pocket calculators, word processors and personal computers.The liquid crystal phase used in the liquid crystal display is normallynematic phase. The liquid crystal display using the nematic liquidcrystal has a serious problem in visible angle dependency, whereindisplay may change in color over angles of view since the nematic liquidcrystal varies in transmittance of light over view angles. The range ofview angle free of any change in color is relatively narrow.

[0003] The following description will focus on the reason why thenematic liquid crystal varies in transmittance of light over viewangles. The liquid crystal molecule has a slender shape having alongitudinal axis. The transmittance of light through the liquid crystaldepends upon an included angle defined by the longitudinal axis of theslender-shaped liquid crystal molecule and a direction of a ray of lighttransmitting through the liquid crystal. For a nematic liquid crystal,it is convenient to direct the attention onto the longitudinal axis ofthe liquid crystal molecules in the center area of a display cell,excluding liquid crystal molecules adjacent to a pair of substratessandwiching the twisted liquid crystal. If no voltage is applied, theliquid crystal molecules in the center area of the cell are oriented sothat the longitudinal axis of the liquid crystal molecules is directedin parallel to the substrate surface. If, however, a voltage is applied,the liquid crystal molecules are moved in a plane perpendicular to thesubstrate surface so that the longitudinal axis of the liquid crystalmolecules is risen up and tilted from the substrate surface asillustrated in FIG. 1. Since the direction of the ray of light dependsupon a relative position of observer to the screen of the display, theincluded angle defined by both the longitudinal axis of the liquidcrystal molecule and the direction of the ray of light is varieddepending upon the change in the relative position of observer to thescreen of the display. As described above, the transmittance of thelight through the liquid crystal depends upon the included angle definedby both the longitudinal axis of the liquid crystal molecule and thedirection of the ray of light. FIG. 1 is a schematic view illustrativeof the twisted nematic liquid crystal molecule which is tilted and risenup from the substrate surface to explain the dependency upon the viewangle of the twisted nematic liquid crystal molecules. For example, asillustrated in FIG. 1, the liquid crystal molecule 5 in the center areaof the liquid cell 11 is risen so that the longitudinal directionthereof is tilted from the substrate surface. The ray of light 14 ahaving been transmitted through the liquid crystal cell is largelydifferent in direction from the longitudinal axis of the liquid crystalmolecule, for which reason the included angle defined by thelongitudinal axis of the liquid crystal molecule and the direction ofthe ray of light 14 a is large. Since the transmittance of the ray oflight having been transmitted through the liquid crystal depends uponthe included angle defined by the longitudinal axis of the liquidcrystal molecule and the direction of the ray of light 14 a, thetransmittance of the ray of light 14 a through the liquid crystal islow. Accordingly, if the observer views the screen in the direction ofan arrow mark 13 a in parallel to the ray of light 14 a, then thetransmittance of the ray of light 14 a through the liquid crystal islow. In contrast, the ray of light 14 b having been transmitted throughthe liquid crystal cell 11 is almost the same in direction as thelongitudinal axis of the liquid crystal molecule, for which reason theincluded angle defined by the longitudinal axis of the liquid crystalmolecule and the direction of the ray of light 14 a is small. Since thetransmittance of the ray of light having been transmitted through theliquid crystal depends upon the included angle defined by thelongitudinal axis of the liquid crystal molecule and the direction ofthe ray of light 14 b, the transmittance of the ray of light 14 bthrough the liquid crystal is high. Accordingly, if the observer viewsthe screen in the direction of an arrow mark 13 b in parallel to the rayof light 14 b, then the transmittance of the ray of light 14 b throughthe liquid crystal is high. As described above, the nematic or twistednematic liquid crystal display has the above problem in a remarkabledependency upon the view angle.

[0004] In order to settle the above problem in the remarkable dependencyupon the view angle, it was proposed to divide the orientation of thetwisted nematic liquid crystal molecules into two different orientationsover two divided areas for the purpose of reduction in dependency uponthe view angle. This technique is disclosed in Japanese laid-open patentpublication No. 63-106624. Two types of areas in different twoorientation directions co-exit in each pixel. FIG. 2 is a schematic viewillustrative of the twisted nematic liquid crystal molecules which aretilted and risen up in different two orientations from the substratesurface to explain the dependency upon the view angle of the twistednematic liquid crystal molecules. Each pixel is divided into two typesof the area differing in orientation by 180 degrees from each otherwherein the two types of area co-exist in a local part of each pixel.The two types of the area differ in view angle dependency by 180 degreesfrom each other and co-exist locally in the each pixel so that thedifferent dependencies of view angle may be canceled totally. If theobserver views the screen of the display in a direction of an arrow mark13 a, then the rays of light 14 a and 14 c are taken into eyes of theobserver. In this case, as well illustrated in FIG. 2, the ray of light14 a have been transmitted through the twisted nematic liquid crystalmolecule 5 which is risen up toward the right-up direction and tiltedfrom the substrate surface. Since the included angle defined by thetransmission direction of the ray of light 14 a and the longitudinalaxis of the liquid crystal molecule is large, the transmittance of theray of light 14 a is low. In contrast, the ray of light 14 c have beentransmitted through the twisted nematic liquid crystal molecule 5 whichis risen up toward the left-up direction and tilted from the substratesurface. Since the included angle defined by the transmission directionof the ray of light 14 c and the longitudinal axis of the liquid crystalmolecule is small, the transmittance of the ray of light 14 c is high.Since the observer can view both the rays of light 14 a and 14 c havinglow and high transmittances, the dependency of the view angle isapparently reduced.

[0005] On the other hand, if the observer views the screen of thedisplay in a different direction of an arrow mark 13 b, then the rays oflight 14 b and 14 d are taken into eyes of the observer. In this case,as well illustrated in FIG. 2, the ray of light 14 b have beentransmitted through the twisted nematic liquid crystal molecule 5 whichis risen up toward the right-up direction and tilted from the substratesurface. Since the included angle defined by the transmission directionof the ray of light 14 b and the longitudinal axis of the liquid crystalmolecule is small, the transmittance of the ray of light 14 b is high.In contrast, the ray of light 14 d have been transmitted through thetwisted nematic liquid crystal molecule 5 which is risen up toward theleft-up direction and tilted from the substrate surface. Since theincluded angle defined by the transmission direction of the ray of light14 d and the longitudinal axis of the liquid crystal molecule is large,the transmittance of the ray of light 14 d is low. Since the observercan view both the rays of light 14 b and 14 d having low and hightransmittances, the dependency of the view angle is apparently reduced.

[0006] The dependency of view angle of the twisted nematic liquidcrystal divided into co-existent different two types of area withreference to FIG. 3 which is a view illustrative of the definitions ofthe direction of observation 13, the polar angle θ and the azimuth angleφ from a liquid crystal cell 11. An evaluation point is set on theorigin ◯ on the liquid crystal cell 11 so that the observer observes theevaluation point on the origin ◯ in the observation direction 13 formeasurement of the transmittance of light. FIG. 4 is a diagramillustrative of variations in transmittance of light through the twistednematic liquid crystal divided into co-existent different two types ofarea of FIG. 3 over variable incident angles when the polar angle isvaried in the range of −70 degrees to +70 degrees with the azimuth anglefixed at 90 degrees. The twisted nematic liquid crystal display isgray-scaled. In the range of the polar angle from −40 degrees to +40degrees, the gray scale is kept in the normal order. If the polar angleis beyond the range of −40 degrees to +40 degrees, the inversion of thegray scale is observed. A distance between adjacent curves of thetransmittances is not constant. The compensation to the dependency ofview angle by dividing the twisted nematic liquid crystal into theco-existent different two types of area is effective but only within therange of the polar angle from 40 degrees to +40 degrees. If the polarangle is beyond the range of the polar angle from −40 degrees to +40degrees, this compensation is ineffective. As described above, thetwisted nematic liquid crystal has the above problem in narrow visibleangle.

[0007] In place of such twisted nematic liquid crystal, theferroelectric liquid crystal having smectic C* phase is attractive dueto its relatively wide visible angle. For example, a surface stabilizedferroelectric liquid crystal mode is disclosed as one of theferroelectric liquid crystal and reported by N. A. Clark and S. T.Lagerawll in Applied Physics Letter Vol. 36 (1989). The ferroelectricliquid crystal is provided in a narrow cell gap so that theferroelectric liquid crystal has the helical free structure whereinliquid crystal director is in the bistable states depending uponapplication of a voltage.

[0008] Alternatively, a unistable mode liquid crystal is disclosed inJapanese laid-open patent application No. 4-212126. Furtheralternatively, a deformed helix ferroelectric mode liquid crystal isdisclosed in Advances in Liquid Crystal Research and Applications, 1980p. 469. Further more, anti-ferroelectric liquid crystal is disclosed inFerro-Electronics Vol. 149, pp. 255.

[0009] Those ferroelectric and anti-ferroelectric liquid crystaldisplays have wide visible angles for the following reasons. Normally,the ferroelectric or anti-ferroelectric liquid crystal is injected intoa cell having been treated with parallel or anti-parallel orientation soas to order the longitudinal axis of the liquid crystal molecules. It isalso disclosed in Japanese laid-open patent publication No. 4-371925that, in order to order the longitudinal axis of the liquid crystalmolecules, the rubbing direction of an upper substrate crosses to therubbing direction of a bottom substrate. For those reasons, it ispossible to deal with the ferroelectric and anti-ferroelectric liquidcrystal as an uniaxial double refraction liquid crystal. In this model,the liquid crystal molecules lie so that the longitudinal axis of theliquid crystal molecules is parallel to the substrate surface. Uponapplication of the voltage or no application of the voltage, the liquidcrystal molecules shows such a motion that the ends of the longitudinalaxis thereof rotates around the normal of the substrate surface and in aplane parallel to the substrate surface so that the locus of thelongitudinal axis on rotation draws two cones which tops faces to eachother. FIG. 5 is a schematic view illustrative of the ferroelectric oranti-ferroelectric liquid crystal molecules showing a rotation motionsuch the locus of the longitudinal axis on rotation draws two coneswhich tops faces to each other. Similarly to the twisted nematic liquidcrystals, the transmittance of light through the ferroelectric oranti-ferroelectric liquid crystal depends upon the included angledefined by both the longitudinal axis of the ferroelectric oranti-ferroelectric liquid crystal molecules and the direction of the rayof light having been transmitted through the ferroelectric oranti-ferroelectric liquid crystal. In FIG. 5, two rays of light 14 a and14 b have been transmitted through a ferroelectric or anti-ferroelectricliquid crystal molecule 5. If the observer views the display screen in adirection 13 a, then the observer observes the ray of light 14 a. If,however, the observer views the display screen in a direction 13 b, thenthe observer observes the ray of light 14 b. The included angle definedbetween the direction of the ray of light 14 a and the longitudinal axisof the ferroelectric or anti-ferroelectric liquid crystal molecule 5 isequal to the included angle defined between the direction of the ray oflight 14 b and the longitudinal axis of the ferroelectric oranti-ferroelectric liquid crystal molecule 5, for which reason thetransmitance of the ray of light 14 a is the same as that of the ray oflight 14 b. The observer can observe the same quality of photon or theintensity of light both in the directions 13 a and 13 b. This means thatif the viewer direction is tilted and varied, then the transmittance ofthe ray of light through the ferroelectric or anti-ferroelectric liquidcrystal molecule 5 is symmetrically varied. This can been said when thedisplay is gray-scaled. Namely, even if the display is gray-scaled, thenthe transmittance of the ray of light through the ferroelectric oranti-ferroelectric liquid crystal molecule 5 is symmetrically varied.FIG. 6 is a diagram illustrative of variations in transmittance of theray of light versus incident angle or view angle in causes ofapplications of various voltages V0<V01<V2<V3 for realizing fourgray-scale display, wherein polar angle of the view direction is variedin the range of −70 degrees to +70 degrees toward directions having theazimuth angles of 0 degree and 180 degrees. The transmittances of theray of light are varied symmetrically with reference to the zero polarangle of the view direction. No inversion on gray scale appears not onlyin the small polar angle range but also near the polar angle of ±70degrees when the voltages V0, V1 and V3 are applied.

[0010] In case of application of the voltage V2, there still remains theproblem in dependency upon view angle. Namely, the transmittance of theray of light increases as the incident angle approaches ±50 degrees. Asthe incident angle or the view angle approaches zero, the transmittanceof the ray of light decreases and is lower by near 10% from when theincident angle approaches ±50 degrees. The ferroelectric oranti-ferroelectric liquid crystal display shows symmetrical variationsin transmittance of the ray of light over incident angles for all of thefour gray-scales corresponding to V0, V1, V2 and V3. Notwithstanding, inthe intermediate gray scale corresponding to V2, the transmittance ofthe ray of light is lower in the front view or at the zero polar angleand as the view direction is tilted from the front view, thetransmittance of the ray of light increases.

[0011] The above described ferroelectric or anti-ferroelectric liquidcrystal display has another problem in flicker in driving the display.Generally, the liquid crystal display is driven by alternating currentdriving wherein periodical applications of positive and subsequentnegative voltages are made in order to avoid destruction of the liquidcrystal due to a direct current component. The ferroelectric oranti-ferroelectric liquid crystal display utilizes the interactionbetween electric field and spontaneous polarization, for which reasonthe ferroelectric or anti-ferroelectric liquid crystal changes inorientation in accordance with the polarity of the applied voltage. Inthe light of optical responsibility, the change in orientation of theferroelectric or anti-ferroelectric liquid crystal molecules correspondsto that the longitudinal axis of the ferroelectric or anti-ferroelectricliquid crystal rotates around the normal of the substrate surface andthe ends of the ferroelectric or anti-ferroelectric liquid crystalrotate in a plane parallel to the substrate surface so that the locus ofthe longitudinal axis on rotation draws two cones which tops faces toeach other.

[0012] If the observer views the display screen in the front direction,then the observer views the ray of light having been transmitted throughthe ferroelectric or anti-ferroelectric liquid crystal molecules in adirection parallel to the normal of the substrate surface, for whichreason the included angle defied between the ray of light and thelongitudinal axis of the ferroelectric or anti-ferroelectric liquidcrystal molecules remains unchanged when the longitudinal axis of theferroelectric or anti-ferroelectric liquid crystal rotates around thenormal of the substrate surface and the ends of the ferroelectric oranti-ferroelectric liquid crystal rotate in a plane parallel to thesubstrate surface so that the locus of the longitudinal axis on rotationdraws two cones which tops faces to each other. Since the transmittanceof the ray of light through the ferroelectric or anti-ferroelectricliquid crystal depends upon the included angle defined between the rayof light and the longitudinal axis of the ferroelectric oranti-ferroelectric liquid crystal molecules, the transmittance remainsunchanged during the above rotation motion of the ferroelectric oranti-ferroelectric liquid crystal molecules.

[0013] If, however, the observer views the display screen in the obliquedirection, then the observer views the ray of light having beentransmitted through the ferroelectric or anti-ferroelectric liquidcrystal molecules in a direction tilted from the normal of the substratesurface, for which reason the included angle defined between the ray oflight and the longitudinal axis of the ferroelectric oranti-ferroelectric liquid crystal molecules is changed when thelongitudinal axis of the ferroelectric or anti-ferroelectric liquidcrystal rotates around the normal of the substrate surface and the endsof the ferroelectric or anti-ferroelectric liquid crystal rotate in aplane parallel to the substrate surface so that the locus of thelongitudinal axis on rotation draws two cones which tops faces to eachother. Since the transmittance of the ray of light through theferroelectric or anti-ferroelectric liquid crystal depends upon theincluded angle defined between the ray of light and the longitudinalaxis of the ferroelectric or anti-ferroelectric liquid crystalmolecules, the transmittance is changed during the above rotation motionof the ferroelectric or anti-ferroelectric liquid crystal molecules.Actually, if the frequency of the applied voltage is about 60 Hz, thenthe phenomenon of flicker appears. The above problem with the flickerprevents realization of the full color wide view angle liquid crystaldisplay.

[0014] In the above circumstances, it is required to develop a novelferroelectric or anti-ferroelectric liquid crystal display within animproved dependency of view angle and being free from flicker inalternating current driving the display.

SUMMARY OF THE INVENTION

[0015] Accordingly, it is an object of the present invention to providea novel ferroelectric or anti-ferroelectric liquid crystal display freefrom the problems as described above.

[0016] It is a further object of the present invention to provide anovel ferroelectric or anti-ferroelectric liquid crystal display withinan improved dependency of view angle.

[0017] It is a further object of the present invention to provide anovel ferroelectric or anti-ferroelectric liquid crystal display freefrom flicker in alternating current driving the display.

[0018] The above and other objects, features and advantages of thepresent invention will be apparent from the following descriptions.

[0019] The first present invention provides a ferroelectric liquidcrystal display including a pair of first and second substrates placedsubstantially in parallel to each other to form a space between thefirst and second substrates so that a ferroelectric liquid crystal isprovided in the space between the first and second substrates, whereinthe ferroelectric liquid crystal is isolated into co-existent differenttwo types of local areas which differ by 90 degrees from each other ininitial orientation direction toward which an optical axis offerroelectric liquid crystal molecules is directed under no electricfield applied to the ferroelectric liquid crystal immediately after theferroelectric liquid crystal has been injected into the space betweenthe first and second substrates.

[0020] The second present invention provides an anti-ferroelectricliquid crystal display including a pair of first and second substratesplaced substantially in parallel to each other to form a space betweenthe first and second substrates so that an anti-ferroelectric liquidcrystal is provided in the space between the first and secondsubstrates, wherein the anti-ferroelectric liquid crystal is isolatedinto co-existent different two types of local areas which differ by 90degrees from each other in initial orientation direction toward which anoptical axis of anti-ferroelectric liquid crystal molecules is directedunder no electric field applied to the anti-ferroelectric liquid crystalimmediately after the anti-ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0021] The third present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby the right angle.

[0022] The fourth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby the right angle.

[0023] The fifth present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0024] The sixth present invention provides an anti-ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal provided inthe space between the first and second orientation films, wherein thefirst orientation film is divided into first and second areas in eachpixel so that the first area is unidirectionally oriented to have afirst orientation direction and the second area is unidirectionallyoriented to have a second orientation direction which differs from thefirst orientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0025] The seventh present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates placed substantially in parallel to each other to forma space between the first and second substrates. A first orientationfilm is provided which extends over an inner surface of the firstsubstrate so that the first orientation film facing to the space. Asecond orientation film is provided which extends over an inner surfaceof the second substrate so that the second orientation film facing tothe space. A ferroelectric liquid crystal is provided in the spacebetween the first and second orientation films, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being anti-parallel tothe second orientation direction whereby the fourth orientationdirection differs from the third orientation direction by the rightangle.

[0026] The eighth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein thefirst orientation film is divided into first and second areas in eachpixel so that the first area is unidirectionally oriented to have afirst orientation direction and the second area is unidirectionallyoriented to have a second orientation direction which differs from thefirst orientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being anti-parallel tothe first orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being anti-parallel tothe second orientation direction whereby the fourth orientationdirection differs from the third orientation direction by the rightangle.

[0027] The ninth present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees+2α, where α is an angle by which an opticalaxis of the ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

[0028] The tenth present invention provides an anti-ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided extends over an inner surface of the firstsubstrate so that the first orientation film facing to the space. Asecond orientation film is provided which extends over an inner surfaceof the second substrate so that the second orientation film facing tothe space. An anti-ferroelectric liquid crystal is provided in the spacebetween the first and second orientation films, wherein entire parts ofthe first orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees+2α, where α is an angle by which an optical axis of theanti-ferroelectric liquid crystal differs in a clockwise direction froma unidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0029] The eleventh present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees−2α, where a is an angle by which an opticalaxis of the ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

[0030] The twelfth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees−2α, where a is an angle by which an opticalaxis of the anti-ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Preferred embodiments according to the present invention will bedescribed in detail with reference to the accompanying drawings.

[0032]FIG. 1 is a schematic view illustrative of the twisted nematicliquid crystal molecule which is tilted and risen up from the substratesurface to explain the dependency upon the view angle of the twistednematic liquid crystal molecules in the first conventional liquidcrystal display.

[0033]FIG. 2 is a schematic view illustrative of the twisted nematicliquid crystal molecules which are tilted and risen up in different twoorientations from the substrate surface to explain the dependency uponthe view angle of the twisted nematic liquid crystal molecules in thesecond conventional liquid crystal display.

[0034]FIG. 3 is a view illustrative of the definitions of the directionof observation 13, the polar angle θ and the azimuth angle φ from aliquid crystal cell 11.

[0035]FIG. 4 is a diagram illustrative of variations in transmittance oflight through the twisted nematic liquid crystal divided intoco-existent different two types of area of FIG. 3 over variable incidentangles when the polar angle is varied in the range of −70 degrees to +70degrees with the azimuth angle fixed at 90 degrees.

[0036]FIG. 5 is a schematic view illustrative of the ferroelectric oranti-ferroelectric liquid crystal molecules showing a rotation motionsuch the locus of the longitudinal axis on rotation draws two coneswhich tops faces to each other.

[0037]FIG. 6 is a diagram illustrative of variations in transmittance ofthe ray of light versus incident angle or view angle in causes ofapplications of various voltages V0<V01<V2<V3 for realizing fourgray-scale display, wherein polar angle of the view direction is variedin the range of −70 degrees to +70 degrees toward directions having theazimuth angles of 0 degree and 180 degrees.

[0038]FIG. 7 is a diagram illustrative of equitransmittance curves ofthe ray of light through a ferroelectric liquid crystal to evaluate adependency of transmittance of the ray of light upon a view angle whenthe optical axis of the ferroelectric liquid crystal is made rotate by25 degrees from the direction defined by the azimuth angles of 0 degreeand 180 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface.

[0039]FIG. 8 is a diagram illustrative of equitransmittance curves ofthe ray of light through a ferroelectric liquid crystal to evaluate adependency of transmittance of the ray of light upon a view angle whenthe optical axis of the ferroelectric liquid crystal is made rotate by25 degrees from the direction defined by the azimuth angles of 90degrees and 270 degrees around the normal to the substrate surface andin a plane parallel to the substrate surface.

[0040]FIG. 9 is a diagram illustrative of equitransmittance curves ofthe ray of light through a ferroelectric liquid crystal to evaluate adependency of transmittance of the ray of light upon a view angle whenthe optical axis of the ferroelectric liquid crystal is made rotate by−25 degrees from the direction defined by the azimuth angles of 0 degreeand 180 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface.

[0041]FIG. 10 is a diagram illustrative of equitransmittance curves ofthe ray of light through a ferroelectric liquid crystal to evaluate adependency of transmittance of the ray of light upon a view angle whenthe optical axis of the ferroelectric liquid crystal is made rotate by−25 degrees from the direction defined by the azimuth angles of 90degrees and 270 degrees around the normal to the substrate surface andin a plane parallel to the substrate surface.

[0042]FIG. 11 is a diagram illustrative of equitransmittance curves ofthe ray of light through a ferroelectric liquid crystal to evaluate adependency of transmittance of the ray of light upon a view angle whenboth the optical properties differing by 90 degrees from each other onthe transmittance of the ray of light though the ferroelectric liquidcrystal are superimposed.

[0043]FIG. 12 is a schematic view illustrative of a liquid crystal cellin accordance with the present invention wherein the ferroelectric oranti-ferroelectric liquid crystal is divided into different two types ofco-existent areas differing in orientation direction from each other bythe right angle in a first embodiment according to the presentinvention.

[0044]FIG. 13 is a schematic view illustrative of a liquid crystal cellin accordance with the present invention wherein the ferroelectric oranti-ferroelectric liquid crystal is divided into different two types ofco-existent areas differing in orientation direction from each other bythe right angle in a second embodiment according to the presentinvention.

[0045]FIG. 14 is a schematic view illustrative of a liquid crystal cellin accordance with the present invention wherein the ferroelectric orante ferroelectric liquid crystal is divided into different two types ofco-existent areas differing in orientation direction from each other bythe right angle in a third embodiment according to the presentinvention.

[0046]FIG. 15 is a schematic view illustrative of a liquid crystal cellin accordance with the present invention wherein the ferroelectric oranti-ferroelectric liquid crystal is divided into different two types ofco-existent areas differing in orientation direction from each other bythe right angle in a fourth embodiment according to the presentinvention.

[0047]FIG. 16 is a view illustrative of the result of observation bypolarizing microscope, wherein the orientations of the liquid crystalare represented by line segments.

[0048]FIG. 17 is a view illustrative of the definitions of the directionof observation 13, the polar angle θ and the azimuth angle φ from aliquid crystal cell 11.

[0049]FIG. 18 is a diagram illustrative of the results of themeasurements of transmittance versus view angle in accordance with thepresent invention.

[0050]FIG. 19 is a plan view illustrative of a strip pattern used in asecond embodiment in accordance with the present invention.

DISCLOSURE OF THE INVENTION

[0051] The first present invention provides a ferroelectric liquidcrystal display including a pair of first and second substrates placedsubstantially in parallel to each other to form a space between thefirst and second substrates so that a ferroelectric liquid crystal isprovided in the space between the first and second substrates, whereinthe ferroelectric liquid crystal is isolated into co-existent differenttwo types of local areas which differ by 90 degrees from each other ininitial orientation direction toward which an optical axis offerroelectric liquid crystal molecules is directed under no electricfield applied to the ferroelectric liquid crystal immediately after theferroelectric liquid crystal has been injected into the space betweenthe first and second substrates.

[0052] It is preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by the right angle.

[0053] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0054] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being anti-parallel tothe second orientation direction whereby the fourth orientationdirection differs from the third orientation direction by the rightangle.

[0055] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees+2α, where α is an angle by which an optical axis of theferroelectric liquid crystal differs in a clockwise direction from aunidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0056] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees−2α, where α is an angle by which an optical axis of theferroelectric liquid crystal differs in a clockwise direction from aunidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0057] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first orientation direction.

[0058] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to an initial orientation direction of any one ofthe co-existent different two types of the local areas.

[0059] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0060] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0061] The second present invention provides an anti-ferroelectricliquid crystal display including a pair of first and second substratesplaced substantially in parallel to each other to form a space betweenthe first and second substrates so that an anti-ferroelectric liquidcrystal is provided in the space between the first and secondsubstrates, wherein the anti-ferroelectric liquid crystal is isolatedinto co-existent different two types of local areas which differ by 90degrees from each other in initial orientation direction toward which anoptical axis of anti-ferroelectric liquid crystal molecules is directedunder no electric field applied to the anti-ferroelectric liquid crystalimmediately after the anti-ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0062] It is preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by the right angle.

[0063] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0064] It is also preferable to farther provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area 4s unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being anti-parallel tothe second orientation direction whereby the fourth orientationdirection differs from the third orientation direction by the rightangle.

[0065] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees+2α, where α is an angle by which an optical axis of theanti-ferroelectric liquid crystal differs in a clockwise direction froma unidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0066] It is also preferable to further provide a first orientation filmextending over an inner surface of the first substrate so that the firstorientation film facing to the space, and a second orientation filmextending over an inner surface of the second substrate so that thesecond orientation film facing to the space, wherein entire parts of thefirst orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees−2α, where α is an angle by which an optical axis of theanti-ferroelectric liquid crystal differs in a clockwise direction froma unidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0067] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first orientation direction.

[0068] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to an initial orientation direction of any one ofthe co-existent different two types of the local areas.

[0069] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0070] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0071] The third present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby the right angle.

[0072] It is preferable that the ferroelectric liquid crystal isisolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of ferroelectric liquid crystal moleculesis directed under no electric field applied to the ferroelectric liquidcrystal immediately after the ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0073] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first orientation direction.

[0074] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second orientation direction.

[0075] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first orientation direction.

[0076] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second orientation direction.

[0077] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first orientation direction.

[0078] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second orientation direction.

[0079] It is also preferable that the co-existent different two types ofthe local areas have substantially the same area as each other.

[0080] It is also preferable that the co-existent different two types ofthe local areas are uniformly distributed.

[0081] The fourth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby the right angle.

[0082] It is preferable that the anti-ferroelectric liquid crystal isisolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of anti-ferroelectric liquid crystalmolecules is directed under no electric field applied to theanti-ferroelectric liquid crystal immediately after theanti-ferroelectric liquid crystal has been injected into the spacebetween the first and second substrates.

[0083] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first orientation direction.

[0084] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second orientation direction.

[0085] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first orientation direction.

[0086] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second orientation direction.

[0087] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first orientation direction.

[0088] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second orientation direction.

[0089] It is also preferable that the co-existent different two types ofthe local areas have substantially the same area as each other.

[0090] It is also preferable that the co-existent different two types ofthe local areas are uniformly distributed.

[0091] The fifth present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0092] It is preferable that the ferroelectric liquid crystal isisolated into different two types of the first and third areas and ofthe second and fourth areas which differ by 90 degrees from each otherin initial orientation direction toward which an optical axis offerroelectric liquid crystal molecules is directed under no electricfield applied to the ferroelectric liquid crystal immediately after theferroelectric liquid crystal has been injected into the space betweenthe first and second substrates.

[0093] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first and third orientation directions.

[0094] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second and fourth orientation directions.

[0095] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first and third orientationdirections.

[0096] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second and fourth orientationdirections.

[0097] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first and third orientationdirections.

[0098] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second and fourth orientationdirections.

[0099] It is also preferable that the first and second areas havesubstantially the same area as each other.

[0100] It is also preferable that the first and second areas areuniformly distributed.

[0101] The sixth present invention provides an anti-ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal provided inthe space between the first and second orientation films, wherein thefirst orientation film is divided into first and second areas in eachpixel so that the first area is unidirectionally oriented to have afirst orientation direction and the second area is unidirectionallyoriented to have a second orientation direction which differs from thefirst orientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being parallel to thefirst orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0102] It is preferable that the anti-ferroelectric liquid crystal isisolated into different two types of the first and third areas and ofthe second and fourth areas which differ by 90 degrees from each otherin initial orientation direction toward which an optical axis ofanti-ferroelectric liquid crystal molecules is directed under noelectric field applied to the anti-ferroelectric liquid crystalimmediately after the anti-ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0103] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first and third orientation directions.

[0104] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second and fourth orientation directions.

[0105] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first and third orientationdirections.

[0106] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second and fourth orientationdirections.

[0107] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first and third orientationdirections.

[0108] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second and fourth orientationdirections.

[0109] It is also preferable that the first and second areas havesubstantially the same area as each other.

[0110] It is also preferable that the first and second areas areuniformly distributed.

[0111] The seventh present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates placed substantially in parallel to each other to forma space between the first and second substrates. A first orientationfilm is provided which extends over an inner surface of the firstsubstrate so that the first orientation film facing to the space. Asecond orientation film is provided which extends over an inner surfaceof the second substrate so that the second orientation film facing tothe space. A ferroelectric liquid crystal is provided in the spacebetween the first and second orientation films, wherein the firstorientation film is divided into first and second areas in each pixel sothat the first area is unidirectionally oriented to have a firstorientation direction and the second area is unidirectionally orientedto have a second orientation direction which differs from the firstorientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being anti-parallel tothe first orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being parallel to thesecond orientation direction whereby the fourth orientation directiondiffers from the third orientation direction by the right angle.

[0112] It is preferable that the ferroelectric liquid crystal isisolated into different two types of the first and third areas and ofthe second and fourth areas which differ by 90 degrees from each otherin initial orientation direction toward which an optical axis offerroelectric liquid crystal molecules is directed under no electricfield applied to the ferroelectric liquid crystal immediately after theferroelectric liquid crystal has been injected into the space betweenthe first and second substrates.

[0113] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first and third orientation directions.

[0114] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second and fourth orientation directions.

[0115] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first and third orientationdirections.

[0116] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second and fourth orientationdirections.

[0117] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first and third orientationdirections.

[0118] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second and fourth orientationdirections.

[0119] It is also preferable that the first and second areas havesubstantially the same area as each other.

[0120] It is also preferable that the first and second areas areuniformly distributed.

[0121] The eighth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein thefirst orientation film is divided into first and second areas in eachpixel so that the first area is unidirectionally oriented to have afirst orientation direction and the second area is unidirectionallyoriented to have a second orientation direction which differs from thefirst orientation direction by the right angle, and wherein the secondorientation film is divided into third and fourth areas in each pixel,and the third area is positioned in correspondence to the first area ina plane view and the fourth area is positioned in correspondence to thesecond area in the plane view so that the third area is unidirectionallyoriented to have a third orientation direction being anti-parallel tothe first orientation direction and the fourth area is unidirectionallyoriented to have a fourth orientation direction being anti-parallel tothe second orientation direction whereby the fourth orientationdirection differs from the third orientation direction by the rightangle.

[0122] It is preferable that the anti-ferroelectric liquid crystal isisolated into different two types of the first and third areas and ofthe second and fourth areas which differ by 90 degrees from each otherin initial orientation direction toward which an optical axis ofanti-ferroelectric liquid crystal molecules is directed under noelectric field applied to the anti-ferroelectric liquid crystalimmediately after the anti-ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0123] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the first and third orientation directions.

[0124] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to the second and fourth orientation directions.

[0125] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the first and third orientationdirections.

[0126] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to the second and fourth orientationdirections.

[0127] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the first and third orientationdirections.

[0128] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to the second and fourth orientationdirections.

[0129] It is also preferable that the first and second areas havesubstantially the same area as each other.

[0130] It is also preferable that the first and second areas areuniformly distributed.

[0131] The ninth present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees+2α, where α is an angle by which an opticalaxis of the ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

[0132] It is preferable that the ferroelectric liquid crystal isisolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of ferroelectric liquid crystal moleculesis directed under no electric field applied to the ferroelectric liquidcrystal immediately after the ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0133] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to an initial orientation direction of any one ofthe co-existent different two types of the local areas.

[0134] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0135] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0136] The tenth present invention provides an anti-ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided extends over an inner surface of the firstsubstrate so that the first orientation film facing to the space. Asecond orientation film is provided which extends over an inner surfaceof the second substrate so that the second orientation film facing tothe space. An anti-ferroelectric liquid crystal is provided in the spacebetween the first and second orientation films, wherein entire parts ofthe first orientation film are unidirectionally oriented to have a firstorientation direction and entire parts of the second orientation filmare unidirectionally oriented to have a second orientation directionwhich differs from the first orientation direction by an angle of 90degrees+2α, where α is an angle by which an optical axis of theanti-ferroelectric liquid crystal differs in a clockwise direction froma unidirectional orientation direction of one of the first and secondorientation films when the remaining one of the first and secondorientation films is not oriented.

[0137] It is also preferable that the anti-ferroelectric liquid crystalis isolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of anti-ferroelectric liquid crystalmolecules is directed under no electric field applied to theanti-ferroelectric liquid crystal immediately after theanti-ferroelectric liquid crystal has been injected into the spacebetween the first and second substrates.

[0138] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to an initial orientation direction of any one ofthe co-existent different two types of the local areas.

[0139] It is also preferable to Other provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0140] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0141] The eleventh present invention provides a ferroelectric liquidcrystal display comprising the following elements. A pair of first andsecond substrates is placed substantially in parallel to each other toform a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. A ferroelectric liquid crystal is provided in thespace between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees−2α, where α is an angle by which an opticalaxis of the ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

[0142] It is preferable that the ferroelectric liquid crystal isisolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of ferroelectric liquid crystal moleculesis directed under no electric field applied to the ferroelectric liquidcrystal immediately after the ferroelectric liquid crystal has beeninjected into the space between the first and second substrates.

[0143] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the first polarizingdirection corresponds to an initial orientation direction of any one ofthe co-existent different two types of the local areas.

[0144] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0145] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0146] The twelfth present invention provides an anti-ferroelectricliquid crystal display comprising the following elements. A pair offirst and second substrates is placed substantially in parallel to eachother to form a space between the first and second substrates. A firstorientation film is provided which extends over an inner surface of thefirst substrate so that the first orientation film facing to the space.A second orientation film is provided which extends over an innersurface of the second substrate so that the second orientation filmfacing to the space. An anti-ferroelectric liquid crystal is provided inthe space between the first and second orientation films, wherein entireparts of the first orientation film are unidirectionally oriented tohave a first orientation direction and entire parts of the secondorientation film are unidirectionally oriented to have a secondorientation direction which differs from the first orientation directionby an angle of 90 degrees−2α, where α is an angle by which an opticalaxis of the anti-ferroelectric liquid crystal differs in a clockwisedirection from a unidirectional orientation direction of one of thefirst and second orientation films when the remaining one of the firstand second orientation films is not oriented.

[0147] It is also preferable that the anti-ferroelectric liquid crystalis isolated into co-existent different two types of local areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of anti-ferroelectric liquid crystalmolecules is directed under no electric field applied to theanti-ferroelectric liquid crystal immediately after theanti-ferroelectric liquid crystal has been injected into the spacebetween the first and second substrates.

[0148] It is also preferable that a first polarizing plate provided onan outer surface of the first substrate and the first polarizing platehaving a first polarizing direction, and a second polarizing plateprovided on an outer surface of the second substrate and the secondpolarizing plate having a second polarizing direction vertical to thefirst polarizing direction, wherein the first polarizing directioncorresponds to an initial orientation direction of any one of theco-existent different two types of the local areas.

[0149] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing directionvertical to the first polarizing direction, wherein the secondpolarizing direction corresponds to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0150] It is also preferable to further provide a first polarizing plateprovided on an outer surface of the first substrate and the firstpolarizing plate having a first polarizing direction, and a secondpolarizing plate provided on an outer surface of the second substrateand the second polarizing plate having a second polarizing direction inparallel to the first polarizing direction, wherein the first and secondpolarizing directions correspond to an initial orientation direction ofany one of the co-existent different two types of the local areas.

[0151] Differently from the present invention, in the twisted nematicliquid crystal display, the twisted nematic liquid crystal moleculespositioned in the enter area and not adjacent to two substrates is risenup from the substrate surface and the longitudinal axis of the twistednematic liquid crystal molecules is tilted from the substrate surface.There are possible two opposite directions of rising up the twistednematic liquid crystal molecules. The first one is the right-updirection and the second one is the left-up direction. In order tocompensate the remarkable dependency of the transmittance of the ray oflight upon view angle, it was proposed to divide the twisted nematicliquid crystal into co-existent different two types of area havingdifferent directions toward which the longitudinal axis of the twistednematic liquid crystal molecules are tilted Up. For this purpose, thesubstrates are subjected to orientation treatments so that theorientation directions are different by 180 degrees between theco-existent different two types of area.

[0152] In contrast, the longitudinal axis of the ferroelectric oranti-ferroelectric liquid crystal rotates around the normal of thesubstrate surface and the ends of the ferroelectric oranti-ferroelectric liquid crystal rotate in a plane parallel to thesubstrate surface so that the locus of the longitudinal axis on rotationdraws two cones which tops faces to each other. Even if the substratesare subjected to orientation treatments so as to divide theferroelectric or anti-ferroelectric liquid crystal into co-existentdifferent two types of area having different directions toward which thelongitudinal axis of the twisted nematic liquid crystal molecules aretilted up, the transmittance of the ray of light through the liquidcrystal is the same between the co-existent different two types of area.This means it is difficult to compensate the dependency of thetransmittance of the ray of light upon the view angle.

[0153] As described above, in accordance with the first, third, fifth,seventh, ninth and eleventh present inventions, however, two substratesare subjected to orientation treatments so that the two substratesdiffer in orientation direction from each other by the right angle or 90degrees so as to divide the ferroelectric liquid crystal intoco-existent different two types of local areas having different initialorientation directions by 90 degrees from each other toward which theoptical axis of the ferroelectric liquid crystal molecules are tiltedup, provided that the transmittance of the ray of light through theliquid crystal is the same between the co-existent different two typesof area. This means it is possible to compensate the uniaxial anisotropyof the transmittance dependency of the ray of light upon the view anglefor the following reasons.

[0154] The ferroelectric liquid crystal is injected into a liquidcrystal cell having orientation films of a unidirectional orientation.Optical axis of the ferroelectric liquid crystal immediately afterinjected into the liquid crystal cell under no voltage application isdirected to correspond to the unidirectional orientation of theorientation films. The direction of the optical axis of theferroelectric liquid crystal immediately after injected into the liquidcrystal cell under no voltage application will hereinafter be referredto as an initial orientation direction.

[0155] The initial orientation direction of the ferroelectric liquidcrystal molecules is made to correspond to the direction defined by theazimuth angles of 0 degree and 180 degrees. FIG. 7 is a diagramillustrative of equitransmittance curves of the ray of light through aferroelectric liquid crystal to evaluate a dependency of transmittanceof the ray of light upon a view angle when the optical axis of theferroelectric liquid crystal is made to rotate by 25 degrees from thedirection defined by the azimuth angles of 0 degree and 180 degreesaround the normal to the substrate surface and in a plane parallel tothe substrate surface. The wavelength of light for measurement is 550nanometers. The transmittance of the ray of light is zero when noferroelectric liquid crystal is inserted and in place two polarizingplates are provided so that polarization directions of the twopolarizing plates are made cross at the right angle. The transmittanceof the ray of light is 1 when no ferroelectric liquid crystal isinserted and in place two polarizing plates are provided so thatpolarization directions of the two polarizing plates are made parallelto each other. The equitransmittance curves of the ray of light througha ferroelectric liquid crystal in FIG. 7 indicates that as the viewangle at which the observer observes the display screen approaches adirection defined by the azimuth angles of 80 degrees and 260 degrees,the distances of the equitransmittance curves are made narrow. Thismeans that as the view angle, at which the observer observes the displayscreen, approaches a direction defined by the azimuth angles of 80degrees and 260 degrees, the variation in transmittance of the ray oflight through the ferroelectric liquid crystal is relatively rapid. Asthe view angle approaches a direction defined by the azimuth angles of−10 degrees and 170 degrees, the distances of the equitransmittancecurves are made wide. This means that as the view angle approaches adirection defined by the azimuth angles of −10 degrees and 170 degrees,the variation in transmittance of the ray of light through theferroelectric liquid crystal is relatively gentle. There are twodirections in which the variation in transmittance of the ray of lightthrough the ferroelectric liquid crystal is relatively rapid andrelatively gentle. The ferroelectric liquid crystal has the uniaxialanisotropy of the view angle dependency such that the rate of variationin transmittance of the ray of light through the ferroelectric liquidcrystal depends upon the azimuth angle.

[0156] The initial orientation direction of the ferroelectric liquidcrystal molecules is made correspond to the direction defined by theazimuth angles of 90 degrees and 270 degrees. FIG. 8 is a diagramillustrative of equitransmittance curves of the ray of light through aferroelectric liquid crystal to evaluate a dependency of transmittanceof the ray of light upon a view angle when the optical axis of theferroelectric liquid crystal is made rotate by 25 degrees from thedirection defined by the azimuth angles of 90 degrees and 270 degreesaround the normal to the substrate surface and in a plane parallel tothe substrate surface. FIG. 11 is a diagram illustrative ofequitransmittance curves of the ray of light through a ferroelectricliquid crystal to evaluate a dependency of transmittance of the ray oflight upon a view angle when both the optical properties differing by 90degrees from each other on the transmittance of the ray of light thoughthe ferroelectric liquid crystal are superimposed. The wavelength oflight for measurement is 550 nanometers. The transmittance of the ray oflight is zero when no ferroelectric liquid crystal is inserted and inplace two polarizing plates are provided so that polarization directionsof the two polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a ferroelectric liquid crystal in FIG. 8 indicates that as theview angle at which the observer observes the display screen approachesa direction defined by the azimuth angles of −10 degrees and 170degrees, the distances of the equitransmittance curves are made narrow.This means that as the view angle, at which the observer observes thedisplay screen, approaches a direction defined by the azimuth angles of−10 degrees and 170 degrees, the variation in transmittance of the rayof light through the ferroelectric liquid crystal is relatively rapid.As the view angle approaches a direction defined by the azimuth anglesof 80 degrees and 260 degrees, the distances of the equitransmittancecurves are made wide. This means that as the view angle approaches adirection defined by the azimuth angles of 80 degrees and 260 degrees,the variation in transmittance of the ray of light through theferroelectric liquid crystal is relatively gentle. There are twodirections in which the variation in transmittance of the ray of lightthrough the ferroelectric liquid crystal is relatively rapid andrelatively gentle. The ferroelectric liquid crystal has the uniaxialanisotropy of the view angle dependency such that the rate of variationin transmittance of the ray of light through the ferroelectric liquidcrystal depends upon the azimuth angle. The uniaxial anisotropy of theview angle dependency of the ferroelectric liquid crystal illustrated inFIG. 8 differs by the azimuth angle of 90 degrees from the uniaxialanisotropy of the view angle dependency of the ferroelectric liquidcrystal illustrated in FIG. 7.

[0157] If both the optical properties on the transmittance of the ray oflight though the ferroelectric liquid crystal illustrated in FIGS. 7 and8 are superimposed, then the unidirectional anisotropy of the view angledependency of the ferroelectric liquid crystal is relaxed thereby toobtain an isotropy of the view angle dependency of the ferroelectricliquid crystal wherein the equitransmittance curves has almost thecircular shape as illustrated in FIG. 11. This means that of theferroelectric liquid crystal molecules the two different areas havinginitial orientation directions differing by 90 degrees from each othercan relax the individual unidirectional anisotropy of the view angledependency so as to provide the isotropy of the view angle dependencywherein the equitransmittance curves has almost the circular shape.Namely, the provision of the above two different areas of theferroelectric liquid crystal molecules having initial orientationdirections differing by 90 degrees from each other changes the indexellipsoid into the circular of the evaluation point of the liquidcrystal cell whereby the dependency of the transmittance of the ray oflight upon the view angle is reduced.

[0158] The above description of the reason why the co-existent twodifferent areas of the ferroelectric liquid crystal molecules havinginitial orientation directions differing by 90 degrees from each othercan reduce the dependency of the transmittance of the ray of light uponthe view angle would be applicable to the anti-ferroelectric liquidcrystal.

[0159] The above structural feature of the provision of the above twodifferent areas of the ferroelectric liquid crystal molecules differingin initial orientation directions by 90 degrees from each other not onlyreduces the dependency of the transmittance of the ray of light upon theview angle but also prevents the flicker for the following reasons.

[0160] The initial orientation direction of the ferroelectric liquidcrystal molecules is made correspond to the direction defined by theazimuth angles of 0 degrees and 180 degrees. FIG. 9 is a diagramillustrative of equitransmittance curves of the ray of light through aferroelectric liquid crystal to evaluate a dependency of transmittanceof the ray of light upon a view angle when the optical axis of theferroelectric liquid crystal is made rotate by −25 degrees from thedirection defined by the azimuth angles of 0 degree and 180 degreesaround the normal to the substrate surface and in a plane parallel tothe substrate surface. The wavelength of light for measurement is 550nanometers. The transmittance of the ray of light is zero when noferroelectric liquid crystal is inserted and in place two polarizingplates are provided so that polarization directions of the twopolarizing plates are made cross at the right angle. The transmittanceof the ray of light is 1 when no ferroelectric liquid crystal isinserted and in place two polarizing plates are provided so thatpolarization directions of the two polarizing plates are made parallelto each other. The equitransmittance curves of the ray of light througha ferroelectric liquid crystal in FIG. 9 indicates that as the viewangle at which the observer observes the display screen approaches adirection defined by the azimuth angles of 100 degrees and 280 degrees,the distances of the equitransmittance curves are made narrow. Thismeans that as the view angle, at which the observer observes the displayscreen, approaches a direction defined by the azimuth angles of 100degrees and 280 degrees, the variation in transmittance of the ray oflight through the ferroelectric liquid crystal is relatively rapid. Asthe view angle approaches a direction defined by the azimuth angles of10 degrees and 90 degrees, the distances of the equitransmittance curvesare made wide. This means that as the view angle approaches a directiondefined by the azimuth angles of 10 degrees and 90 degrees, thevariation in transmittance of the ray of light through the ferroelectricliquid crystal is relatively gentle. There are two directions in whichthe variation in transmittance of the ray of light through theferroelectric liquid crystal is relatively rapid and relatively gentle.The ferroelectric liquid crystal has the uniaxial anisotropy of the viewangle dependency such that the rate of variation in transmittance of theray of light through the ferroelectric liquid crystal depends upon theazimuth angle.

[0161] The initial orientation direction of the ferroelectric liquidcrystal molecules is made correspond to the direction defined by theazimuth angles of 90 degrees and 270 degrees. FIG. 10 is a diagramillustrative of equitransmittance curves of the ray of light through aferroelectric liquid crystal to evaluate a dependency of transmittanceof the ray of light upon a view angle when the optical axis of theferroelectric liquid crystal is made rotate by −25 degrees from thedirection defined by the azimuth angles of 90 degrees and 270 degreesaround the normal to the substrate surface and in a plane parallel tothe substrate surface. FIG. 11 is a diagram illustrative ofequitransmittance curves of the ray of light through a ferroelectricliquid crystal to evaluate a dependency of transmittance of the ray oflight upon a view angle when both the optical properties differing by 90degrees from each other on the transmittance of the ray of light thoughthe ferroelectric liquid crystal are superimposed. The wavelength oflight for measurement is 550 nanometers. The transmittance of the ray oflight is zero when no ferroelectric liquid crystal is inserted and inplace two polarizing plates are provided so that polarization directionsof the two polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a ferroelectric liquid crystal in FIG. 8 indicates that as theview angle at which the observer observes the display screen approachesa direction defined by the azimuth angles of 10 degrees and 190 degrees,the distances of the equitransmittance curves are made narrow. Thismeans that as the view angle, at which the observer observes the displayscreen, approaches a direction defined by the azimuth angles of 10degrees and 90 degrees, the variation in transmittance of the ray oflight through the ferroelectric liquid crystal is relatively rapid. Asthe view angle approaches a direction defined by the azimuth angles of100 degrees and 280 degrees, the distances of the equitransmittancecurves are made wide. This means that as the view angle approaches adirection defined by the azimuth angles of 100 degrees and 280 degrees,the variation in transmittance of the ray of light through theferroelectric liquid crystal is relatively gentle. There are twodirections in which the variation in transmittance of the ray of lightthrough the ferroelectric liquid crystal is relatively rapid andrelatively gentle. The ferroelectric liquid crystal has the uniaxialanisotropy of the view angle dependency such that the rate of variationin transmittance of the ray of light through the ferroelectric liquidcrystal depends upon the azimuth angle. The uniaxial anisotropy of theview angle dependency of the ferroelectric liquid crystal illustrated inFIG. 8 differs by the azimuth angle of 90 degrees from the uniaxialanisotropy of the view angle dependency of the ferroelectric liquidcrystal illustrated in FIG. 9. If both the optical properties on thetransmittance of the ray of light though the ferroelectric liquidcrystal illustrated in FIGS. 9 and 10 are superimposed, then theunidirectional anisotropy of the view angle dependency of theferroelectric liquid crystal is relaxed thereby to obtain an isotropy ofthe view angle dependency of the ferroelectric liquid crystal whereinthe equitransmittance curves has almost the circular shape asillustrated in FIG. 11. The difference in polarity of the appliedvoltage correspond to the difference in direction of the above rotationof the optical axis of the ferroelectric liquid crystal molecules. Thismeans that of the ferroelectric liquid crystal molecules the twodifferent areas having initial orientation directions differing by 90degrees from each other can make the optical transmittance propertiesremain unchanged over opposite polarities of the applied voltage. Thisfurther means even if the observer observes the screen in the obliquedirection, no problem with flicker is raised.

[0162] The above description of the reason why the co-existent twodifferent areas of the ferroelectric liquid crystal molecules havinginitial orientation directions differing by 90 degrees from each othercan prevent the flicker would be applicable to the anti-ferroelectricliquid crystal.

[0163] Accordingly, it is apparent from the above descriptions that theco-existent two different areas of the ferroelectric liquid crystalmolecules having initial orientation directions differing by 90 degreesfrom each other not only can reduce the dependency of the transmittanceof the ray of light upon the view angle but also prevents the flicker.

[0164] In accordance with the present invention, the ferroelectricliquid crystal is inserted between the two substrates having uniaxialorientations differing by the right angle from each other. If theorientation processes for the substrates is not uniform, then theferroelectric liquid crystal is partially oriented in one uniaxialorientation of first one of the substrates and partially oriented in theopposite uniaxial orientation of second one of the substrates. Thismeans that the two different types of fine areas of the ferroelectricliquid crystal co-exist in each pixel.

[0165] The following descriptions will focus on a black displayperformance. If, contrary to the present invention, the angle betweenthe two orientation directions of the two substrates is different from90 degrees, it is apparent from the above descriptions that theco-existent two different types of areas of the ferroelectric liquidcrystal molecules having initial orientation directions differing by anangle but not 90 degrees from each other not only can not reducesufficiently the uniaxial anisotropy of the light transmittancedependency upon the view angle but also can not prevent sufficiently theflicker.

[0166] Further if, contrary to the present invention, the aboveco-existent two different types of areas of the ferroelectric liquidcrystal having initial orientation directions differing by an angle ofnot 90 degrees from each other is placed between two polarizing plateshaving polarizing axes differing by the right angle from each other,then the above co-existent two different types of areas of theferroelectric liquid crystal differ from each other in the includedangles defined by the optical axis of the ferroelectric liquid crystaland the polarizing axis of the polarizing plate, whereby it is difficultto obtain the desired exact black display.

[0167] If, however, in accordance with the present invention, the aboveco-existent two different types of areas of the ferroelectric liquidcrystal having initial orientation directions differing by the rightangle from each other is placed between two polarizing plates havingpolarizing axes differing by the right angle from each other, then theabove co-existent two different types of areas of the ferroelectricliquid crystal are the same as each other in the light of the includedangle defined by the optical axis of the ferroelectric liquid crystaland the polarizing axis of the polarizing plate, whereby it is possibleto obtain the desired exact black display. Further, it is possible toprevent the flicker when alternating current driving of the display iscarried out and the observer views the screen in an oblique direction.

[0168] As described above, the second, fourth, sixth, eighth, tenth andtwelfth present inventions are respectively different from the first,third, fifth, seventh, ninth and eleventh present inventions only in theliquid crystal is anti-ferroelectric liquid crystal in place of theferroelectric liquid crystal. The above descriptions for the first,third, fifth, seventh, ninth and eleventh present inventions arecommonly applicable to the second, fourth, sixth, eighth, tenth andtwelfth present inventions.

[0169] Namely, in accordance with the second, fourth, sixth, eighth,tenth and twelfth present inventions, however, two substrates aresubjected to orientation treatments so that the two substrates differ inorientation direction from each other by the right angle or 90 degreesso as to divide the anti-ferroelectric liquid crystal into co-existentdifferent two types of local areas having different initial orientationdirections by 90 degrees from each other toward which the optical axisof the anti-ferroelectric liquid crystal molecules are tilted up,provided that the transmittance of the ray of light through the liquidcrystal is the same between the co-existent different two types of area.This means it possible to compensate the uniaxial anisotropy of thetransmittance dependency of the ray of light upon the view angle for thefollowing reasons.

[0170] The anti-ferroelectric liquid crystal is injected into a liquidcrystal cell having orientation films of a unidirectional orientation.Optical axis of the anti-ferroelectric liquid crystal immediately afterinjected into the liquid crystal cell under no voltage application isdirected to correspond to the unidirectional orientation of theorientation films. The direction of the optical axis of theanti-ferroelectric liquid crystal immediately after injected into theliquid crystal cell under no voltage application will hereinafter bereferred to as an initial orientation direction.

[0171] The initial orientation direction of the anti-ferroelectricliquid crystal molecules is made correspond to the direction deemed bythe azimuth angles of 0 degrees and 180 degrees. FIG. 7 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when the opticalaxis of the anti-ferroelectric liquid crystal is made rotate by 25degrees from the direction defined by the azimuth angles of 0 degreesand 180 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface. The wavelength of light formeasurement is 550 nanometers. The transmittance of the ray of light iszero when no anti-ferroelectric liquid crystal is inserted and in placetwo polarizing plates are provided so that polarization directions ofthe two polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no anti-ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a anti-ferroelectric liquid crystal in FIG. 7 indicates that asthe view angle at which the observer observes the display screenapproaches a direction defined by the azimuth angles of 80 degrees and260 degrees, the distances of the equitransmittance curves are madenarrow. This means that as the view angle, at which the observerobserves the display screen, approaches a direction defined by theazimuth angles of 80 degrees and 260 degrees, the variation intransmittance of the ray of light through the anti-ferroelectric liquidcrystal is relatively rapid. As the view angle approaches a directiondefined by the azimuth angles of −10 degrees and 170 degrees, thedistances of the equitransmittance curves are made wide. This means thatas the view angle approaches a direction defined by the azimuth anglesof −10 degrees and 170 degrees, the variation in transmittance of theray of light through the anti-ferroelectric liquid crystal is relativelygentle. There are two directions in which the variation in transmittanceof the ray of light through the anti-ferroelectric liquid crystal isrelatively rapid and relatively gentle. The anti-ferroelectric liquidcrystal has the uniaxial anisotropy of the view angle dependency suchthat the rate of variation in transmittance of the ray of light throughthe anti-ferroelectric liquid crystal depends upon the azimuth angle.

[0172] The initial orientation direction of the anti-ferroelectricliquid crystal molecules is made correspond to the direction defined bythe azimuth angles of 90 degrees and 270 degrees. FIG. 8 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when the opticalaxis of the anti-ferroelectric liquid crystal is made rotate by 25degrees from the direction defined by the azimuth angles of 90 degreesand 270 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface. FIG. 11 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when both theoptical properties differing by 90 degrees from each other on thetransmittance of the ray of light though the anti-ferroelectric liquidcrystal are superimposed. The wavelength of light for measurement is 550nanometers. The transmittance of the ray of light is zero when noanti-ferroelectric liquid crystal is inserted and in place twopolarizing plates are provided so that polarization directions of thetwo polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no anti-ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a anti-ferroelectric liquid crystal in FIG. 8 indicates that asthe view angle at which the observer observes the display screenapproaches a direction defined by the azimuth angles of −10 degrees and170 degrees, the distances of the equitransmittance curves are madenarrow. This means that as the view angle, at which the observerobserves the display screen, approaches a direction defined by theazimuth angles of −10 degrees and 170 degrees, the variation intransmittance of the ray of light through the anti-ferroelectric liquidcrystal is relatively rapid. As the view angle approaches a directiondefined by the azimuth angles of 80 degrees and 260 degrees, thedistances of the equitransmittance curves are made wide. This means thatas the view angle approaches a direction defined by the azimuth anglesof 80 degrees and 260 degrees, the variation in transmittance of the rayof light through the anti-ferroelectric liquid crystal is relativelygentle. There are two directions in which the variation in transmittanceof the ray of light through the anti-ferroelectric liquid crystal isrelatively rapid and relatively gentle. The anti-ferroelectric liquidcrystal has the uniaxial anisotropy of the view angle dependency suchthat the rate of variation in transmittance of the ray of light throughthe anti-ferroelectric liquid crystal depends upon the azimuth angle.The uniaxial anisotropy of the view angle dependency of theanti-ferroelectric liquid crystal illustrated in FIG. 8 differs by theazimuth angle of 90 degrees from the uniaxial anisotropy of the viewangle dependency of the anti-ferroelectric liquid crystal illustrated inFIG. 7. If both the optical properties on the transmittance of the rayof light though the anti-ferroelectric liquid crystal illustrated inFIGS. 7 and 8 are superimposed, then the unidirectional anisotropy ofthe view angle dependency of the anti-ferroelectric liquid crystal isrelaxed thereby to obtain an isotropy of the view angle dependency ofthe anti-ferroelectric liquid crystal wherein the equitransmittancecurves has almost the circular shape as illustrated in FIG. 11. Thismanes that of the anti-ferroelectric liquid crystal molecules the twodifferent areas having initial orientation directions differing by 90degrees from each other can relax the individual unidirectionalanisotropy of the view angle dependency so as to provide the isotropy ofthe view angle dependency wherein the equitransmittance curves hasalmost the circular shape. Namely, the provision of the above twodifferent areas of the anti-ferroelectric liquid crystal moleculeshaving initial orientation directions differing by 90 degrees from eachother changes the index ellipsoid into the circular of the evaluationpoint of the liquid crystal cell whereby the dependency of thetransmittance of the ray of light upon the view angle is reduced.

[0173] The above description of the reason why the co-existent twodifferent areas of the anti-ferroelectric liquid crystal moleculeshaving initial orientation directions differing by 90 degrees from eachother can reduce the dependency of the transmittance of the ray of lightupon the view angle would be applicable to the anti-anti-ferroelectricliquid crystal.

[0174] The above structural feature of the provision of the above twodifferent areas of the anti-ferroelectric liquid crystal moleculesdiffering in initial orientation directions by 90 degrees from eachother not only reduces the dependency of the transmittance of the ray oflight upon the view angle but also prevents the flicker for thefollowing reasons.

[0175] The initial orientation direction of the anti-ferroelectricliquid crystal molecules is made correspond to the direction defined bythe azimuth angles of 0 degrees and 180 degrees. FIG. 9 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when the opticalaxis of the anti-ferroelectric liquid crystal is made rotate by −25degrees from the direction defined by the azimuth angles of 0 degreesand 180 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface. The wavelength of light formeasurement is 550 nanometers. The transmittance of the ray of light iszero when no anti-ferroelectric liquid crystal is inserted and in placetwo polarizing plates are provided so that polarization directions ofthe two polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no anti-ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a anti-ferroelectric liquid crystal in FIG. 9 indicates that asthe view angle at which the observer observes the display screenapproaches a direction defined by the azimuth angles of 100 degrees and280 degrees, the distances of the equitransmittance curves are madenarrow. This means that as the view angle, at which the observerobserves the display screen, approaches a direction defined by theazimuth angles of 100 degrees and 280 degrees, the variation intransmittance of the ray of light through the anti-ferroelectric liquidcrystal is relatively rapid. As the view angle approaches a directiondefined by the azimuth angles of 10 degrees and 190 degrees, thedistances of the equitransmittance curves are made wide. This means thatas the view angle approaches a direction defined by the azimuth anglesof 10 degrees and 90 degrees, the variation in transmittance of the rayof light through the anti-ferroelectric liquid crystal is relativelygentle. There are two directions in which the variation in transmittanceof the ray of light through the anti-ferroelectric liquid crystal isrelatively rapid and relatively gentle. The anti-ferroelectric liquidcrystal has the uniaxial anisotropy of the view angle dependency suchthat the rate of variation in transmittance of the ray of light throughthe anti-ferroelectric liquid crystal depends upon the azimuth angle.

[0176] The initial orientation direction of the anti-ferroelectricliquid crystal molecules is made correspond to the direction defined bythe azimuth angles of 90 degrees and 270 degrees. FIG. 10 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when the opticalaxis of the anti-ferroelectric liquid crystal is made rotate by −25degrees from the direction defined by the azimuth angles of 90 degreesand 270 degrees around the normal to the substrate surface and in aplane parallel to the substrate surface. FIG. 11 is a diagramillustrative of equitransmittance curves of the ray of light through aanti-ferroelectric liquid crystal to evaluate a dependency oftransmittance of the ray of light upon a view angle when both theoptical properties differing by 90 degrees from each other on thetransmittance of the ray of light though the anti-ferroelectric liquidcrystal are superimposed. The wavelength of light for measurement is 550nanometers. The transmittance of the ray of light is zero when noanti-ferroelectric liquid crystal is inserted and in place twopolarizing plates are provided so that polarization directions of thetwo polarizing plates are made cross at the right angle. Thetransmittance of the ray of light is 1 when no anti-ferroelectric liquidcrystal is inserted and in place two polarizing plates are provided sothat polarization directions of the two polarizing plates are madeparallel to each other. The equitransmittance curves of the ray of lightthrough a anti-ferroelectric liquid crystal in FIG. 8 indicates that asthe view angle at which the observer observes the display screenapproaches a direction defined by the azimuth angles of 10 degrees and90 degrees, the distances of the equitransmittance curves are madenarrow. This means that as the view angle, at which the observerobserves the display screen, approaches a direction defined by theazimuth angles of 10 degrees and 190 degrees, the variation intransmittance of the ray of light through the anti-ferroelectric liquidcrystal is relatively rapid. As the view angle approaches a directiondefined by the azimuth angles of 100 degrees and 280 degrees, thedistances of the equitransmittance curves are made wide. This means thatas the view angle approaches a direction defined by the azimuth anglesof 100 degrees and 280 degrees, the variation in transmittance of theray of light through the anti-ferroelectric liquid crystal is relativelygentle. There are two directions in which the variation in transmittanceof the ray of light through the anti-ferroelectric liquid crystal isrelatively rapid and relatively gentle. The anti-ferroelectric liquidcrystal has the uniaxial anisotropy of the view angle dependency suchthat the rate of variation in transmittance of the ray of light throughthe anti-ferroelectric liquid crystal depends upon the azimuth angle.The uniaxial anisotropy of the view angle dependency of theanti-ferroelectric liquid crystal illustrated in FIG. 8 differs by theazimuth angle of 90 degrees from the uniaxial anisotropy of the viewangle dependency of the anti-ferroelectric liquid crystal illustrated inFIG. 9.

[0177] If both the optical properties on the transmittance of the ray oflight though the anti-ferroelectric liquid crystal illustrated in FIGS.9 and 10 are superimposed, then the unidirectional anisotropy of theview angle dependency of the anti-ferroelectric liquid crystal isrelaxed thereby to obtain an isotropy of the view angle dependency ofthe anti-ferroelectric liquid crystal wherein the equitransmittancecurves has almost the circular shape as illustrated in FIG. 11. Thedifference in polarity of the applied voltage correspond to thedifference in direction of the above rotation of the optical axis of theanti-ferroelectric liquid crystal molecules. This means that of theanti-ferroelectric liquid crystal molecules the two different areashaving initial orientation directions differing by 90 degrees from eachother can make the optical transmittance properties remain unchangedover opposite polarities of the applied voltage. This further means evenif the observer observes the screen in the oblique direction, no problemwith flicker is raised.

[0178] The above description of the reason why the co-existent twodifferent areas of the anti-ferroelectric liquid crystal moleculeshaving initial orientation directions differing by 90 degrees from eachother can prevent the flicker would be applicable to theanti-anti-ferroelectric liquid crystal.

[0179] Accordingly, it is apparent from the above descriptions that theco-existent two different areas of the anti-ferroelectric liquid crystalmolecules having initial orientation directions differing by 90 degreesfrom each other not only can reduce the dependency of the transmittanceof the ray of light upon the view angle but also prevents the flicker.

[0180] In accordance with the present invention, the anti-ferroelectricliquid crystal is inserted between the two substrates having uniaxialorientations differing by the right angle from each other. If theorientation processes for the substrates is not uniform, then theanti-ferroelectric liquid crystal is partially oriented in one uniaxialorientation of first one of the substrates and partially oriented in theopposite uniaxial orientation of second one of the substrates. Thismeans that the two different types of fine areas of theanti-ferroelectric liquid crystal co-exist in each pixel.

[0181] The following descriptions will focus on a black displayperformance. If, contrary to the present invention, the angle betweenthe two orientation directions of the two substrates is different from90 degrees, it is apparent from the above descriptions that theco-existent two different types of areas of the anti-ferroelectricliquid crystal molecules having initial orientation directions differingby an angle but not 90 degrees from each other not only can not reducesufficiently the uniaxial anisotropy of the light transmittancedependency upon the view angle but also can not prevent sufficiently theflicker.

[0182] Further if, contrary to the present invention, the aboveco-existent two different types of areas of the anti-ferroelectricliquid crystal having initial orientation directions differing by anangle of not 90 degrees from each other is placed between two polarizingplates having polarizing axes differing by the right angle from eachother, then the above co-existent two different types of areas of theanti-ferroelectric liquid crystal differ from each other in the includedangles defined by the optical axis of the anti-ferroelectric liquidcrystal and the polarizing axis of the polarizing plate, whereby it isdifficult to obtain the desired exact black display.

[0183] If, however, in accordance with the present invention, the aboveco-existent two different types of areas of the anti-ferroelectricliquid crystal having initial orientation directions differing by theright angle from each other is placed between two polarizing plateshaving polarizing axes differing by the right angle from each other,then the above co-existent two different types of areas of theanti-ferroelectric liquid crystal are the same as each other in thelight of the included angle defined by the optical axis of theanti-ferroelectric liquid crystal and the polarizing axis of thepolarizing plate, whereby it is possible to obtain the desired exactblack display. Further, it is possible to prevent the flicker whenalternating current driving of the display is carried out and theobserver views the screen in an oblique direction.

Embodiments

[0184] First Embodiment

[0185] A first embodiment according to the present invention will bedescribed with reference to FIG. 12. Indium thin oxide films aredeposited on a pair of glass substrates 2 to form transparent electrodes3. Orientation film materials are applied on the transparent electrodes3 for subsequent burning the orientation film materials to formorientation films 4 over the transparent electrodes 3. The orientationfilm on the top substrate is subjected to a rubbing treatment in a firstdirection 12 a whilst the orientation film on the bottom substrate issubjected to another rubbing treatment in a second direction 12 b whichhas the right angle to the direction 12 a. Spacer materials aredistributed on the peripheral region of the substrate to fabricate aliquid crystal cell. Ferroelectric or anti-ferroelectric liquid crystalis heated up to a temperature at which the liquid crystal enters into anisotropic phase before injection into the cell for subsequent cooleddown to the room temperature. The liquid crystal is divided intoco-existent two different types of area wherein first one has the liquidcrystal orientated in the first direction and the second one has theliquid crystal orientated in the second direction.

[0186] As a liquid crystal, FLC-9200 was used which is commerciallyavailable from Hoffmann La Roche and it is disclosed in ISID 94 Digest430 page that this liquid crystal may be used in DHF mode. The aboveorientation films 4 may be made by spin-coating AL-1051 commerciallyavailable from Nippon Synthetic Rubber for subsequent burning at atemperature of 200° C. for one hour. As a spacer material, micro pearlsof 3 micrometers commercially available from Shimizu Kasei. The liquidcrystal may be heated up to 76° C. prior to the injection into the cellbefore cooling down to the room temperature.

[0187] The orientation of the liquid crystal was confirmed by use of aBerek compensator and polarizing microscope. It was confirmed that theliquid crystal 5 is divided into the different two types of areasdiffering in orientation direction by the right angle from each other. Aresult of the observation by the polarizing microscope is illustrated inFIG. 16, wherein the orientations of the liquid crystal are representedby line segments. The size of the areas is about 25 micrometers/squares.

[0188] The ratio of the different two types of areas of the liquidcrystal may be changed by changing the intensity of the rubbingtreatment to be subjected to the orientation films. In this embodiment,however, the intensity of the rubbing treatment is constant between thetwo substrates so that the different two types of areas of the liquidcrystal have almost the same area.

[0189] The above liquid crystal cell is placed between a pair of thepolarizing plates having polarizing axes vertical to each other. One ofthe two different orientation directions of the liquid crystal is madecorrespond to the absorption axis of one of the polarizing plates.Coordinates are set so that the above orientation directioncorresponding to the absorption axis is made correspond to the directionof 0 degrees−180 degrees as illustrated in FIG. 17. Results of themeasurements of transmittance versus view angle are illustrated in FIG.18 from which it can be understood that the transmittance almost remainsunchanged in the range of −40 degrees to +40 degrees without drop of thetransmittance in the front direction when gray scale display is made.

[0190] Second Embodiment

[0191] A second embodiment according to the present invention will bedescribed with reference to FIG. 13. Indium thin oxide films aredeposited on a pair of glass substrates 2 to form transparent electrodes3. Orientation film materials are applied on the transparent electrodes3 for subsequent burning the orientation film materials to formorientation films 4 over the transparent electrodes 3. The orientationfilm on the top substrate is divided into a plurality of pairs ofdifferent two areas for each pixel wherein the first type of the area issubjected to a rubbing treatment in a first direction 12 a whilst thesecond type of the area is subjected to another rubbing treatment in athird direction 12 c which has the right angle to the first direction 12a. The orientation film on the bottom substrate is also divided into aplurality of pairs of different two areas for each pixel wherein thefirst type of the area is subjected to a rubbing treatment in a seconddirection 12 b which is parallel to the first direction 12 a whilst thesecond type of the area is subjected to another rubbing treatment in afourth direction 12 d which is parallel to the third direction 12 c andhas the right angle to the second direction 12 d. The above rubbingdiffering in orientation direction may be made by the following tworubbing treatments. In the first step, the orientation film on the topsubstrate is subjected to the rubbing treatment in the first direction12 a uniformly over the entire parts thereof whilst the orientation filmon the bottom substrate is subjected to the rubbing treatment in thesecond direction 12 b uniformly over the entire parts thereof.Photo-resist films applied over the orientation films on the twosubstrates. The photo-resist films are then exposed to an ultra-violetray through a strip pattern 8 having 100 micrometers in width of stripsand apertures as illustrated in FIG. 19. Thereafter the development ismade to selectively remove the photo-resist films for subsequent bakingthe same to form a mask pattern 9. The strip pattern has the width of100 micrometers and the gas of 100 micrometers so as to utilize thesuperimposition of the optical properties of the different two types ofthe areas. The gap and the width of the strip pattern are the same aseach other so that the different two types of the areas of the liquidcrystal have the same ratio in area. Notwithstanding, the ratio in areaof the different two types of the areas of the liquid crystal may bechanged by changing the ratio of the width to the gap of the strippattern. The strip pattern is provided on the orientation film on thetop substrate which has been already rubbing-treated in the firstdirection 12 a so that the direction of the strip pattern is vertical tothe first direction 12 a. The strip pattern is provided on theorientation film on the bottom substrate which has been alreadyrubbing-treated in the second direction 12 b so that the direction ofthe strip pattern is vertical to the second direction 12 b. By use ofthe strip patterns, the further ribbing treatment is made so that theorientation film on the top substrate is subjected to a third ribbingtreatment in the third direction 12 c which is vertical to the firstdirection 12 a whilst the orientation film on the bottom substrate issubjected to a fourth ribbing treatment in the fourth direction 12 dwhich is vertical to the second direction 12 b and in parallel to thethird direction 12 c. The used strip pattern is then removed. Spacermaterials are distributed on the peripheral region of the substrate tofabricate a liquid crystal cell. Ferroelectric or anti-ferroelectricliquid crystal is heated up to a temperature at which the liquid crystalenters into an isotropic phase before injection into the cell forsubsequent cooled down to the room temperature. The liquid crystal isdivided into co-existent two different types of area wherein first onehas the liquid crystal orientated in the first direction and the secondone has the liquid crystal orientated in the second direction.

[0192] As a liquid crystal, FLC-9200 was used which is commerciallyavailable from Hoffmann La Roche and it is disclosed in ISID 94 Digest430 page that this liquid crystal may be used in DBF mode. The aboveorientation films 4 may be made by spin-coating AL-1051 commerciallyavailable from Nippon Synthetic Rubber for subsequent burning at atemperature of 200° C. for one hour. As a spacer material, micro pearlsof 3 micrometers commercially available from Shimizu Kasei. The liquidcrystal may be heated up to 76° C. prior to the injection into the cellbefore cooling down to the room temperature.

[0193] The orientation of the liquid crystal was confirmed by use of aBerek compensator and polarizing microscope. It was confirmed thatliquid crystal is divided into a plurality of pairs of different twoareas differing in orientation direction from each other by the rightangle.

[0194] The above liquid crystal cell is placed between a pair of thepolarizing plates having polarizing axes vertical to each other. One ofthe two different orientation directions of the liquid crystal is madecorrespond to the absorption axis of one of the polarizing plates.Coordinates are set so that the above orientation directioncorresponding to the absorption axis is made correspond to the directionof 0 degrees−180 degrees as illustrated in FIG. 17. Results of themeasurements of transmittance versus view angle are illustrated in FIG.18 from which it can be understood that the transmittance almost remainsunchanged in the range of −40 degrees to +40 degrees without drop of thetransmittance in the front direction when gray scale display is made.The isotropy of the transmittance in the polar angle direction from thefront view is further improved as compared to the first embodimentbecause the different two areas of the liquid crystal differing inorientation direction from each other by the right angle have the sametotal area as each other.

[0195] Third Embodiment

[0196] A third embodiment according to the present invention will bedescribed with reference to FIG. 14. Indium thin oxide films aredeposited on a pair of glass substrates 2 to form transparent electrodes3. Orientation film materials are applied on the transparent electrodes3 for subsequent burning the orientation film materials to formorientation films 4 over the transparent electrodes 3. The orientationfilm on the top substrate is divided into a plurality of pairs ofdifferent two areas for each pixel wherein the first type of the area issubjected to a rubbing treatment in a first direction 12 a whilst thesecond type of the area is subjected to another rubbing treatment in athird direction 12 c which has the right angle to the first direction 12a. The orientation film on the bottom substrate is also divided into aplurality of pairs of different two areas for each pixel wherein thefirst type of the area is subjected to a rubbing treatment in a seconddirection 12 b which is anti-parallel to the first direction 12 a whilstthe second type of the area is subjected to another rubbing treatment ina fourth direction 12 d which is anti-parallel to the third direction 12c and has the right angle to the second direction 12 d. The aboverubbing differing in orientation direction may be made by the followingtwo rubbing treatments. In the first step, the orientation film on thetop substrate is subjected to the rubbing treatment in the firstdirection 12 a uniformly over the entire parts thereof whilst theorientation film on the bottom substrate is subjected to the rubbingtreatment in the second direction 12 b uniformly over the entire partsthereof. Photo-resist films applied over the orientation films on thetwo substrates. The photo-resist films are then exposed to anultra-violet ray through a strip pattern 8 having 100 micrometers inwidth of strips and apertures as illustrated in FIG. 19. Thereafter thedevelopment is made to selectively remove the photo-resist films forsubsequent baking the same to form a mask pattern 9. The strip patternhas the width of 100 micrometers and the gas of 100 micrometers so as toutilize the superimposition of the optical properties of the differenttwo types of the areas. The gap and the width of the strip pattern arethe same as each other so that the different two types of the areas ofthe liquid crystal have the same ratio in area. Notwithstanding, theratio in area of the different two types of the areas of the liquidcrystal may be changed by changing the ratio of the width to the gap ofthe strip pattern. The strip pattern is provided on the orientation filmon the top substrate which has been already rubbing-treated in the firstdirection 12 a so that the direction of the strip pattern is vertical tothe first direction 12 a. The strip pattern is provided on theorientation film on the bottom substrate which has been alreadyrubbing-treated in the second direction 12 b so that the direction ofthe strip pattern is vertical to the second direction 12 b. By use ofthe strip patterns, the further ribbing treatment is made so that theorientation film on the top substrate is subjected to a third ribbingtreatment in the third direction 12 c which is vertical to the firstdirection 12 a whilst the orientation film on the bottom substrate issubjected to a fourth ribbing treatment in the fourth direction 12 dwhich is vertical to the second direction 12 b and in anti-parallel tothe third direction 12 c. The used strip pattern is then removed. Spacermaterials are distributed on the peripheral region of the substrate tofabricate a liquid crystal cell. Ferroelectric or anti-ferroelectricliquid crystal is heated up to a temperature at which the liquid crystalenters into an isotropic phase before injection into the cell forsubsequent cooled down to the room temperature. The liquid crystal isdivided into co-existent two different types of area wherein first onehas the liquid crystal orientated in the first direction and the secondone has the liquid crystal orientated in the second direction.

[0197] As a liquid crystal, FLC-9200 was used which is commerciallyavailable from Hoffmann La Roche and it is disclosed in ISID 94 Digest430 page that this liquid crystal may be used in DHF mode. The aboveorientation films 4 may be made by spin-coating AL-1051 commerciallyavailable from Nippon Synthetic Rubber for subsequent burning at atemperature of 200° C. for one hour. As a spacer material, micro pearlsof 3 micrometers commercially available from Shimizu Kasei. The liquidcrystal may be heated up to 76° C. prior to the injection into the cellbefore cooling down to the room temperature.

[0198] The orientation of the liquid crystal was confirmed by use of aBerek compensator and polarizing microscope. It was confirmed thatliquid crystal is divided into a plurality of pairs of different twoareas differing in orientation direction from each other by the rightangle.

[0199] The above liquid crystal cell is placed between a pair of thepolarizing plates having polarizing axes vertical to each other. One ofthe two different orientation directions of the liquid crystal is madecorrespond to the absorption axis of one of the polarizing plates.Coordinates are set so that the above orientation directioncorresponding to the absorption axis is made correspond to the directionof 0 degrees−180 degrees as illustrated in FIG. 17. Results of themeasurements of transmittance versus view angle are illustrated in FIG.18 from which it can be understood that the transmittance almost remainsunchanged in the range of −40 degrees to +40 degrees without drop of thetransmittance in the front direction when gray scale display is made.The isotropy of the transmittance in the polar angle direction from thefront view is further improved as compared to the first embodimentbecause the different two areas of the liquid crystal differing inorientation direction from each other by the right angle have the sametotal area as each other.

[0200] Fourth Embodiment

[0201] A fourth embodiment according to the present invention will bedescribed with reference to FIG. 15. Indium thin oxide films aredeposited on a pair of glass substrates 2 to form transparent electrodes3. Orientation film materials are applied on the transparent electrodes3 for subsequent burning the orientation film materials to formorientation films 4 over the transparent electrodes 3. The ferroelectricor anti-ferroelectric liquid crystal is such a liquid crystal that ifonly one of the orientation films on the top and bottom substrates isoriented in a reference orientation direction and if the ferroelectricor anti-ferroelectric liquid crystal is injected into the top and bottomsubstrates, then the ferroelectric or anti-ferroelectric liquid crystalis oriented so that an optical axis of the ferroelectric oranti-ferroelectric liquid crystal is tilted in a plane parallel to thesubstrate surfaces from the reference orientation direction by an angleα in the clockwise direction. The orientation film on the top substrateis then subjected to a rubbing treatment in an orientation direction 12a which differs and tilts from the reference orientation direction 12 bby an angle of 90 degrees+2α in the plane parallel to the substratesurfaces in the clockwise direction. Alternatively, in order to matchthe different type of the liquid crystal, it is also possible that theorientation film on the top substrate may be subjected to a rubbingtreatment in an orientation direction which differs and tilts from thereference orientation direction 12 b by an angle of 90 degrees−2α in theplane parallel to the substrate surfaces in the clockwise direction.Further alternatively, in order to match the further different type ofthe liquid crystal, it is also possible that the orientation film on thetop substrate may be subjected to a rubbing treatment in an orientationdirection which differs and tilts from the reference orientationdirection 12 b by an angle of 90 degrees+2 a in the plane parallel tothe substrate surfaces in the anti-clockwise direction. Furthermorealternatively, in order to match the furthermore different type of theliquid crystal, it is also possible that the orientation film on the topsubstrate may be subjected to a rubbing treatment in an orientationdirection which differs and tilts from the reference orientationdirection 12 b by an angle of 90 degrees−2α in the plane parallel to thesubstrate surfaces in the anti-clockwise direction. Spacer materials aredistributed on the peripheral region of the substrate to fabricate aliquid crystal cell. Ferroelectric or anti-ferroelectric liquid crystalis heated up to a temperature at which the liquid crystal enters into anisotropic phase before injection into the cell for subsequent cooleddown to the room temperature. The liquid crystal is divided intoco-existent two different types of area wherein first one has the liquidcrystal orientated in the first direction and the second one has theliquid crystal orientated in the second direction.

[0202] As a liquid crystal, anti-ferroelectric liquid crystal CS-4001was used. The optical axis of the anti-ferroelectric liquid crystalCS-4001 is tilted in the plane parallel to the substrate surfaces fromthe reference orientation direction by 5 degrees in the clockwisedirection. The orientation films on the top and bottom substrates differin orientation direction from each other by 100 degrees in the clockwisedirection in the plane parallel to the substrate surfaces. The aboveorientation films 4 may be made by spin-coating AL-1251 commerciallyavailable from Nippon Synthetic Rubber for subsequent burning at atemperature of 180° C. for one hour. As a spacer material, micro pearlsof 2 micrometers commercially available from Shimizu Kasei. The liquidcrystal may be heated up to 80° C. prior to the injection into the cellbefore cooling down to the room temperature at a cooling rate of 0.2°C./min.

[0203] The orientation of the liquid crystal was confirmed by use of aBerek compensator and polarizing microscope. It was confirmed that theliquid crystal 5 is divided into the different two types of areasdiffering in orientation direction by the right angle from each other. Aresult of the observation by the polarizing microscope is illustrated inFIG. 16, wherein the orientations of the liquid crystal are representedby line segments. The size of the areas is about 25 micrometers/squares.Equitransmittance curves as illustrated in FIG. 11 of the ray of lightthrough a ferroelectric liquid crystal are obtained when a voltage isapplied across the liquid crystal. If another voltage having an oppositepolarity to the above voltage is applied across the liquid crystal, thenequitransmittance curves are obtained which are similar to theequitransmittance curves as illustrated in FIG. 11. This means that itis possible to suppress the flicker.

[0204] The angle by which the two orientation films over the substratesdiffer in orientation direction is decided in accordance with the typeof the liquid crystal and may be given by =90°+C.×α, where α is theangle by which an optical axis of the ferroelectric oranti-ferroelectric liquid crystal is tilted in the clockwise direction(C=1) or anti-clockwise direction (C=−1) in the plane parallel to thesubstrate surfaces from the reference orientation direction if only oneof the orientation films on the top and bottom substrates is oriented ina reference orientation direction and if the ferroelectric oranti-ferroelectric liquid crystal is injected into the top and bottomsubstrates.

[0205] The ratio of the different two types of areas of the liquidcrystal may be changed by changing the intensity of the rubbingtreatment to be subjected to the orientation films. In this embodiment,however, the intensity of the rubbing treatment is constant between thetwo substrates so that the different two types of areas of the liquidcrystal have almost the same area.

[0206] The above liquid crystal cell is placed between a pair of thepolarizing plates having polarizing axes vertical to each other. One ofthe two different orientation directions of the liquid crystal is madecorrespond to the absorption axis of one of the polarizing plates.Coordinates are set so that the above orientation directioncorresponding to the absorption axis is made correspond to the directionof 0 degrees−180 degrees as illustrated in FIG. 17. Results of themeasurements of transmittance versus view angle are illustrated in FIG.18 from which it can be understood that the transmittance almost remainsunchanged in the range of −40 degrees to +40 degrees without drop of thetransmittance in the front direction when gray scale display is made.

[0207] The present invention may be applicable to not only the DBF modeof the ferroelectric liquid crystal but also SSFLC mode of theferroelectric liquid crystal as well as a single stable mode of theferroelectric liquid crystal in addition any modes of the anti-liquidcrystals.

[0208] Whereas modifications of the present invention will be apparentto a person having ordinary skill in the art, to which the inventionpertains, it is to be understood that embodiments as shown and describedby way of illustrations are by no means intended to be considered in alimiting sense. Accordingly, it is to be intended to cover by claims allmodifications which fall within the spirit and scope of the presentinvention.

What is claimed is:
 1. A ferroelectric liquid crystal displaycomprising: a pair of first and second substrates placed substantiallyin parallel to each other to form a space between said first and secondsubstrates; a first orientation film extending over an inner surface ofsaid first substrate so that said first orientation film facing to saidspace; a second orientation film extending over an inner surface of saidsecond substrate so that said second orientation film facing to saidspace; and a ferroelectric liquid crystal provided in said space betweensaid first and second orientation films, wherein said first orientationfilm is divided into first and second areas in each pixel so that saidfirst area is unidirectionally oriented to have a first orientationdirection and said second area is unidirectionally oriented to have asecond orientation direction which differs from said first orientationdirection by the right angle, and wherein said second orientation filmis divided into third and fourth areas in each pixel, and said thirdarea is positioned in correspondence to said first area in a plane viewand said fourth area is positioned in correspondence to said second areain said plane view so that said third area is unidirectionally orientedto have a third orientation direction being parallel to said firstorientation direction and said fourth area is unidirectionally orientedto have a fourth orientation direction being parallel to said secondorientation direction whereby said fourth orientation direction differsfrom said third orientation direction by the right angle.
 2. Theferroelectric liquid crystal display as claimed in claim 1, wherein saidferroelectric liquid crystal is isolated into different two types ofsaid first and third areas and of said second and fourth areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of ferroelectric liquid crystal moleculesis directed under no electric field applied to said ferroelectric liquidcrystal immediately after said ferroelectric liquid crystal has beeninjected into said space between said first and second substrates. 3.The ferroelectric liquid crystal display as claimed in claim 2, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction vertical to said first polarizingdirection, wherein said first polarizing direction corresponds to saidfirst and third orientation directions.
 4. The ferroelectric liquidcrystal display as claimed in claim 2, further comprising: a firstpolarizing plate provided on an outer surface of said first substrateand said first polarizing plate having a first polarizing direction; anda second polarizing plate provided on an outer surface of said secondsubstrate and said second polarizing plate having a second polarizingdirection vertical to said first polarizing direction, wherein saidfirst polarizing direction corresponds to said second and fourthorientation directions.
 5. The ferroelectric liquid crystal display asclaimed in claim 2, further comprising: a first polarizing plateprovided on an outer surface of said first substrate and said firstpolarizing plate having a first polarizing direction; and a secondpolarizing plate provided on an outer surface of said second substrateand said second polarizing plate having a second polarizing directionvertical to said first polarizing direction, wherein said secondpolarizing direction corresponds to said first and third orientationdirections.
 6. The ferroelectric liquid crystal display as claimed inclaim 2, further comprising: a first polarizing plate provided on anouter surface of said first substrate and said first polarizing platehaving a first polarizing direction; and a second polarizing plateprovided on an outer surface of said second substrate and said secondpolarizing plate having a second polarizing direction vertical to saidfirst polarizing direction, wherein said second polarizing directioncorresponds to said second and fourth orientation directions.
 7. Theferroelectric liquid crystal display as claimed in claim 2, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction; and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction in parallel to said first polarizingdirection, wherein said first and second polarizing directionscorrespond to said first and third orientation directions.
 8. Theferroelectric liquid crystal display as claimed in claim 2, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction; and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction in parallel to said first polarizingdirection, wherein said first and second polarizing directionscorrespond to said second and fourth orientation directions.
 9. Theferroelectric liquid crystal display as claimed in claim 1, wherein saidfirst and second areas have substantially the same area as each other.10. The ferroelectric liquid crystal display as claimed in claim 1,wherein said first and second areas are uniformly distributed.
 11. Ananti-ferroelectric liquid crystal display comprising: a pair of firstand second substrates placed substantially in parallel to each other toform a space between said first and second substrates; a firstorientation film extending over an inner surface of said first substrateso that said first orientation film facing to said space; a secondorientation film extending over an inner surface of said secondsubstrate so that said second orientation film facing to said space; andan anti-ferroelectric liquid crystal provided in said space between saidfirst and second orientation films, wherein said first orientation filmis divided into first and second areas in each pixel so that said firstarea is unidirectionally oriented to have a first orientation directionand said second area is unidirectionally oriented to have a secondorientation direction which differs from said first orientationdirection by the right angle, and wherein said second orientation filmis divided into third and fourth areas in each pixel, and said thirdarea is positioned in correspondence to said first area in a plane viewand said fourth area is positioned in correspondence to said second areain said plane view so that said third area is unidirectionally orientedto have a third orientation direction being parallel to said firstorientation direction and said fourth area is unidirectionally orientedto have a fourth orientation direction being parallel to said secondorientation direction whereby said fourth orientation direction differsfrom said third orientation direction by the right angle.
 12. Theanti-ferroelectric liquid crystal display as claimed in claim 11,wherein said anti-ferroelectric liquid crystal is isolated intodifferent two types of said first and third areas and of said second andfourth areas which differ by 90 degrees from each other in initialorientation direction toward which an optical axis of anti-ferroelectricliquid crystal molecules is directed under no electric field applied tosaid anti-ferroelectric liquid crystal immediately after saidanti-ferroelectric liquid crystal has been injected into said spacebetween said first and second substrates.
 13. The anti-ferroelectricliquid crystal display as claimed in claim 12, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction vertical to said first polarizing direction,wherein said first polarizing direction corresponds to said first andthird orientation directions.
 14. The anti-ferroelectric liquid crystaldisplay as claimed in claim 12, further comprising: a first polarizingplate provided on an outer surface of said first substrate and saidfirst polarizing plate having a first polarizing direction; and a secondpolarizing plate provided on an outer surface of said second substrateand said second polarizing plate having a second polarizing directionvertical to said first polarizing direction, wherein said firstpolarizing direction corresponds to said second and fourth orientationdirections.
 15. The anti-ferroelectric liquid crystal display as claimedin claim 12, farther comprising: a first polarizing plate provided on anouter surface of said first substrate and said first polarizing platehaving a first polarizing direction; and a second polarizing plateprovided on an outer surface of said second substrate and said secondpolarizing plate having a second polarizing direction vertical to saidfirst polarizing direction, wherein said second polarizing directioncorresponds to said first and third orientation directions.
 16. Theanti-ferroelectric liquid crystal display as claimed in claim 12,further comprising: a first polarizing plate provided on an outersurface of said first substrate and said first polarizing plate having afirst polarizing direction; and a second polarizing plate provided on anouter surface of said second substrate and said second polarizing platehaving a second polarizing direction vertical to said first polarizingdirection, wherein said second polarizing direction corresponds to saidsecond and fourth orientation directions.
 17. The anti-ferroelectricliquid crystal display as claimed in claim 12, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction in parallel to said first polarizing direction,wherein said first and second polarizing directions correspond to saidfirst and third orientation directions.
 18. The anti-ferroelectricliquid crystal display as claimed in claim 12, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction in parallel to said first polarizing direction,wherein said first and second polarizing directions correspond to saidsecond and fourth orientation directions.
 19. The anti-ferroelectricliquid crystal display as claimed in claim 11, wherein said first andsecond areas have substantially the same area as each other.
 20. Theanti-ferroelectric liquid crystal display as claimed in claim 11,wherein said first and second areas are uniformly distributed.
 21. Aferroelectric liquid crystal display comprising: a pair of first andsecond substrates placed substantially in parallel to each other to forma space between said first and second substrates; a first orientationfilm extending over an inner surface of said first substrate so thatsaid first orientation film facing to said space; a second orientationfilm extending over an inner surface of said second substrate so thatsaid second orientation film facing to said space; and a ferroelectricliquid crystal provided in said space between said first and secondorientation films, wherein said first orientation film is divided intofirst and second areas in each pixel so that said first area isunidirectionally oriented to have a first orientation direction and saidsecond area is unidirectionally oriented to have a second orientationdirection which differs from said first orientation direction by theright angle, and wherein said second orientation film is divided intothird and fourth areas in each pixel, and said third area is positionedin correspondence to said first area in a plane view and said fourtharea is positioned in correspondence to said second area in said planeview so that said third area is unidirectionally oriented to have athird orientation direction being parallel to said first orientationdirection and said fourth area is unidirectionally oriented to have afourth orientation direction being anti-parallel to said secondorientation direction whereby said fourth orientation direction differsfrom said third orientation direction by the right angle.
 22. Theferroelectric liquid crystal display as claimed in claim 21, whereinsaid ferroelectric liquid crystal is isolated into different two typesof said first and third areas and of said second and fourth areas whichdiffer by 90 degrees from each other in initial orientation directiontoward which an optical axis of ferroelectric liquid crystal moleculesis directed under no electric field applied to said ferroelectric liquidcrystal immediately after said ferroelectric liquid crystal has beeninjected into said space between said first and second substrates. 23.The ferroelectric liquid crystal display as claimed in claim 22, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction; and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction vertical to said first polarizingdirection, wherein said first polarizing direction corresponds to saidfirst and third orientation directions.
 24. The ferroelectric liquidcrystal display as claimed in claim 22, further comprising: a firstpolarizing plate provided on an outer surface of said first substrateand said first polarizing plate having a first polarizing direction anda second polarizing plate provided on an outer surface of said secondsubstrate and said second polarizing plate having a second polarizingdirection vertical to said first polarizing direction, wherein saidfirst polarizing direction corresponds to said second and fourthorientation directions.
 25. The ferroelectric liquid crystal display asclaimed in claim 22, further comprising: a first polarizing plateprovided on an outer surface of said first substrate and said firstpolarizing plate having a first polarizing direction; and a secondpolarizing plate provided on an outer surface of said second substrateand said second polarizing plate having a second polarizing directionvertical to said first polarizing direction, wherein said secondpolarizing direction corresponds to said first and third orientationdirections.
 26. The ferroelectric liquid crystal display as claimed inclaim 22, further comprising: a first polarizing plate provided on anouter surface of said first substrate and said first polarizing platehaving a first polarizing direction; and a second polarizing plateprovided on an outer surface of said second substrate and said secondpolarizing plate having a second polarizing direction vertical to saidfirst polarizing direction, wherein said second polarizing directioncorresponds to said second and fourth orientation directions.
 27. Theferroelectric liquid crystal display as claimed in claim 22, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction; and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction in parallel to said first polarizingdirection, wherein said first and second polarizing directionscorrespond to said first and third orientation directions.
 28. Theferroelectric liquid crystal display as claimed in claim 22, furthercomprising: a first polarizing plate provided on an outer surface ofsaid first substrate and said first polarizing plate having a firstpolarizing direction; and a second polarizing plate provided on an outersurface of said second substrate and said second polarizing plate havinga second polarizing direction in parallel to said first polarizingdirection, wherein said first and second polarizing directionscorrespond to said second and fourth orientation directions.
 29. Theferroelectric liquid crystal display as claimed in claim 21, whereinsaid first and second areas have substantially the same area as eachother.
 30. The ferroelectric liquid crystal display as claimed in claim21, wherein said first and second areas are uniformly distributed. 31.An anti-ferroelectric liquid crystal display comprising: a pair of firstand second substrates placed substantially in parallel to each other toform a space between said first and second substrates; a firstorientation film extending over an inner surface of said first substrateso that said first orientation film facing to said space; a secondorientation film extending over an inner surface of said secondsubstrate so that said second orientation film facing to said space; andan anti-ferroelectric liquid crystal provided in said space between saidfirst and second orientation films, wherein said first orientation filmis divided into first and second areas in each pixel so that said firstarea is unidirectionally oriented to have a first orientation directionand said second area is unidirectionally oriented to have a secondorientation direction which differs from said first orientationdirection by the right angle, and wherein said second orientation filmis divided into third and fourth areas in each pixel, and said thirdarea is positioned in correspondence to said first area in a plane viewand said fourth area is positioned in correspondence to said second areain said plane view so that said third area is unidirectionally orientedto have a third orientation direction being parallel to said firstorientation direction and said fourth area is unidirectionally orientedto have a fourth orientation direction being anti-parallel to saidsecond orientation direction whereby said fourth orientation directiondiffers from said third orientation direction by the right angle. 32.The anti-ferroelectric liquid crystal display as claimed in claim 31,wherein said anti-ferroelectric liquid crystal is isolated intodifferent two types of said first and third areas and of said second andfourth areas which differ by 90 degrees from each other in initialorientation direction toward which an optical axis of anti-ferroelectricliquid crystal molecules is directed under no electric field applied tosaid anti-ferroelectric liquid crystal immediately after saidanti-ferroelectric liquid crystal has been injected into said spacebetween said first and second substrates.
 33. The anti-ferroelectricliquid crystal display as claimed in claim 32, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction vertical to said first polarizing direction,wherein said first polarizing direction corresponds to said first andthird orientation directions.
 34. The anti-ferroelectric liquid crystaldisplay as claimed in claim 32, further comprising: a first polarizingplate provided on an outer surface of said first substrate and saidfirst polarizing plate having a first polarizing direction; and a secondpolarizing plate provided on an outer surface of said second substrateand said second polarizing plate having a second polarizing directionvertical to said first polarizing direction, wherein said firstpolarizing direction corresponds to said second and fourth orientationdirections.
 35. The anti-ferroelectric liquid crystal display as claimedin claim 32, further comprising: a first polarizing plate provided on anouter surface of said first substrate and said first polarizing platehaving a first polarizing direction; and a second polarizing plateprovided on an outer surface of said second substrate and said secondpolarizing plate having a second polarizing direction vertical to saidfirst polarizing direction, wherein said second polarizing directioncorresponds to said first and third orientation directions.
 36. Theanti-ferroelectric liquid crystal display as claimed in claim 32,further comprising: a first polarizing plate provided on an outersurface of said first substrate and said first polarizing plate having afirst polarizing direction; and a second polarizing plate provided on anouter surface of said second substrate and said second polarizing platehaving a second polarizing direction vertical to said first polarizingdirection, wherein said second polarizing direction corresponds to saidsecond and fourth orientation directions.
 37. The anti-ferroelectricliquid crystal display as claimed in claim 32, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction in parallel to said first polarizing direction,wherein said first and second polarizing directions correspond to saidfirst and third orientation directions.
 38. The anti-ferroelectricliquid crystal display as claimed in claim 32, further comprising: afirst polarizing plate provided on an outer surface of said firstsubstrate and said first polarizing plate having a first polarizingdirection; and a second polarizing plate provided on an outer surface ofsaid second substrate and said second polarizing plate having a secondpolarizing direction in parallel to said first polarizing direction,wherein said first and second polarizing directions correspond to saidsecond and fourth orientation directions.
 39. The anti-ferroelectricliquid crystal display as claimed in claim 31, wherein said first andsecond areas have substantially the same area as each other.
 40. Theanti-ferroelectric liquid crystal display as claimed in claim 31,wherein said first and second areas are uniformly distributed.